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Chemistry AIChapter 4
A Atom(Section 41)
1 Democritus (460BC-370BC)
The smallest part of an element that retains its identity during a chemical reaction
1st to suggest the idea of an atom He believed they were indestructible and indivisible He never experimentally tested his idea
2 Daltonrsquos Atomic Theory (1766-1844)
12 year old English teacher and chemist
Atomic Theory
1 All elements are composed of tiny indivisible particles called atoms2 All atoms of one element are exactly alike but they differ from the atoms of a separate element3 Atoms of different elements can physically mix or chemically combine4 Chemical reactions occur when atoms are separated joined or rearranged Atoms of one element however are never changed into atoms of another element as a result of a chemical reaction
3 Size
The radii of most atoms fall in the range of 50-200pmScanning tunneling microscopes are used to observe atoms (Page 100 Pg103 Figure 43)
A Structure of the atom
1 JJTomson (1856-1940)
Modification of the Atomic Theory
He used a cathode ray tube to show the presence of negatively charged particles called electronsElectrons are negatively charged subatomic particlescathode ray tube in TV
cathode demonstration and explanation
2 Eugen Goldstein (1850-1930)
Used the canal rays in a cathode ray tube to discover protonsProtons are positively charged subatomic units
3 James Chadwick (1891-1974)
Confirmed the existence of neutronsNeutrons are subatomic particles with no charge but with a mass equal to that of a proton
4 Ernest Rutherford (1871-1937)
Previously Thomsonrsquos model of the atom resembled chocolate cookie dough with the dough containing the protons and neutrons and the chocolate chips being the electrons
a The Gold Foil ExperimentSteps of the experiment(Figure 47)
1 Released positively charged alpha particles from a radioactive source towards a very thin sheet of gold foil
2 the beam of particles struck the gold foil
a The Gold Foil Experiment
Results
1 Most of the particles went straight through the foil
2 Some of the particles were deflected to the side
3 Some of the particles reflected directly back at the source
animation of experiment
1The atom is mostly empty space where the electrons are located (1)
2The atom has a nucleus which is a tiny dense central core (2)
3The nucleus is positive containing the protons and neutrons (3)
Conclusions
Based of the results from his experiment Rutherford developed the following theory of the atom
b Rutherfordrsquos Atomic Model
Bohr modified Rutherfordrsquos model to include newer discoveries about how the energy of an atom changes Bohr proposed that an electron is found only in specific circular paths or orbits around the nucleus
Bohr said that each possible electron orbit had fixed energy and these fixed energies of an electron are called energy levels
5 Niels Bohr model (1913)
The fixed energy levels are much like the rungs on a ladder and an electron cannot exist between these energy levels For an electron to move to another energy level they have to gain the correct amount of energy
The energy levels are not equally spaced and are closer together the further the electron gets from the nucleus
Bohrrsquos model worked well for the hydrogen atom but failed to explain the behavior of many other atoms
animated Bohr model
The amount of energy required to move from one energy level to the next
a quantum
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
2 Daltonrsquos Atomic Theory (1766-1844)
12 year old English teacher and chemist
Atomic Theory
1 All elements are composed of tiny indivisible particles called atoms2 All atoms of one element are exactly alike but they differ from the atoms of a separate element3 Atoms of different elements can physically mix or chemically combine4 Chemical reactions occur when atoms are separated joined or rearranged Atoms of one element however are never changed into atoms of another element as a result of a chemical reaction
3 Size
The radii of most atoms fall in the range of 50-200pmScanning tunneling microscopes are used to observe atoms (Page 100 Pg103 Figure 43)
A Structure of the atom
1 JJTomson (1856-1940)
Modification of the Atomic Theory
He used a cathode ray tube to show the presence of negatively charged particles called electronsElectrons are negatively charged subatomic particlescathode ray tube in TV
cathode demonstration and explanation
2 Eugen Goldstein (1850-1930)
Used the canal rays in a cathode ray tube to discover protonsProtons are positively charged subatomic units
3 James Chadwick (1891-1974)
Confirmed the existence of neutronsNeutrons are subatomic particles with no charge but with a mass equal to that of a proton
4 Ernest Rutherford (1871-1937)
Previously Thomsonrsquos model of the atom resembled chocolate cookie dough with the dough containing the protons and neutrons and the chocolate chips being the electrons
a The Gold Foil ExperimentSteps of the experiment(Figure 47)
1 Released positively charged alpha particles from a radioactive source towards a very thin sheet of gold foil
2 the beam of particles struck the gold foil
a The Gold Foil Experiment
Results
1 Most of the particles went straight through the foil
2 Some of the particles were deflected to the side
3 Some of the particles reflected directly back at the source
animation of experiment
1The atom is mostly empty space where the electrons are located (1)
2The atom has a nucleus which is a tiny dense central core (2)
3The nucleus is positive containing the protons and neutrons (3)
Conclusions
Based of the results from his experiment Rutherford developed the following theory of the atom
b Rutherfordrsquos Atomic Model
Bohr modified Rutherfordrsquos model to include newer discoveries about how the energy of an atom changes Bohr proposed that an electron is found only in specific circular paths or orbits around the nucleus
Bohr said that each possible electron orbit had fixed energy and these fixed energies of an electron are called energy levels
5 Niels Bohr model (1913)
The fixed energy levels are much like the rungs on a ladder and an electron cannot exist between these energy levels For an electron to move to another energy level they have to gain the correct amount of energy
The energy levels are not equally spaced and are closer together the further the electron gets from the nucleus
Bohrrsquos model worked well for the hydrogen atom but failed to explain the behavior of many other atoms
animated Bohr model
The amount of energy required to move from one energy level to the next
a quantum
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
3 Size
The radii of most atoms fall in the range of 50-200pmScanning tunneling microscopes are used to observe atoms (Page 100 Pg103 Figure 43)
A Structure of the atom
1 JJTomson (1856-1940)
Modification of the Atomic Theory
He used a cathode ray tube to show the presence of negatively charged particles called electronsElectrons are negatively charged subatomic particlescathode ray tube in TV
cathode demonstration and explanation
2 Eugen Goldstein (1850-1930)
Used the canal rays in a cathode ray tube to discover protonsProtons are positively charged subatomic units
3 James Chadwick (1891-1974)
Confirmed the existence of neutronsNeutrons are subatomic particles with no charge but with a mass equal to that of a proton
4 Ernest Rutherford (1871-1937)
Previously Thomsonrsquos model of the atom resembled chocolate cookie dough with the dough containing the protons and neutrons and the chocolate chips being the electrons
a The Gold Foil ExperimentSteps of the experiment(Figure 47)
1 Released positively charged alpha particles from a radioactive source towards a very thin sheet of gold foil
2 the beam of particles struck the gold foil
a The Gold Foil Experiment
Results
1 Most of the particles went straight through the foil
2 Some of the particles were deflected to the side
3 Some of the particles reflected directly back at the source
animation of experiment
1The atom is mostly empty space where the electrons are located (1)
2The atom has a nucleus which is a tiny dense central core (2)
3The nucleus is positive containing the protons and neutrons (3)
Conclusions
Based of the results from his experiment Rutherford developed the following theory of the atom
b Rutherfordrsquos Atomic Model
Bohr modified Rutherfordrsquos model to include newer discoveries about how the energy of an atom changes Bohr proposed that an electron is found only in specific circular paths or orbits around the nucleus
Bohr said that each possible electron orbit had fixed energy and these fixed energies of an electron are called energy levels
5 Niels Bohr model (1913)
The fixed energy levels are much like the rungs on a ladder and an electron cannot exist between these energy levels For an electron to move to another energy level they have to gain the correct amount of energy
The energy levels are not equally spaced and are closer together the further the electron gets from the nucleus
Bohrrsquos model worked well for the hydrogen atom but failed to explain the behavior of many other atoms
animated Bohr model
The amount of energy required to move from one energy level to the next
a quantum
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
A Structure of the atom
1 JJTomson (1856-1940)
Modification of the Atomic Theory
He used a cathode ray tube to show the presence of negatively charged particles called electronsElectrons are negatively charged subatomic particlescathode ray tube in TV
cathode demonstration and explanation
2 Eugen Goldstein (1850-1930)
Used the canal rays in a cathode ray tube to discover protonsProtons are positively charged subatomic units
3 James Chadwick (1891-1974)
Confirmed the existence of neutronsNeutrons are subatomic particles with no charge but with a mass equal to that of a proton
4 Ernest Rutherford (1871-1937)
Previously Thomsonrsquos model of the atom resembled chocolate cookie dough with the dough containing the protons and neutrons and the chocolate chips being the electrons
a The Gold Foil ExperimentSteps of the experiment(Figure 47)
1 Released positively charged alpha particles from a radioactive source towards a very thin sheet of gold foil
2 the beam of particles struck the gold foil
a The Gold Foil Experiment
Results
1 Most of the particles went straight through the foil
2 Some of the particles were deflected to the side
3 Some of the particles reflected directly back at the source
animation of experiment
1The atom is mostly empty space where the electrons are located (1)
2The atom has a nucleus which is a tiny dense central core (2)
3The nucleus is positive containing the protons and neutrons (3)
Conclusions
Based of the results from his experiment Rutherford developed the following theory of the atom
b Rutherfordrsquos Atomic Model
Bohr modified Rutherfordrsquos model to include newer discoveries about how the energy of an atom changes Bohr proposed that an electron is found only in specific circular paths or orbits around the nucleus
Bohr said that each possible electron orbit had fixed energy and these fixed energies of an electron are called energy levels
5 Niels Bohr model (1913)
The fixed energy levels are much like the rungs on a ladder and an electron cannot exist between these energy levels For an electron to move to another energy level they have to gain the correct amount of energy
The energy levels are not equally spaced and are closer together the further the electron gets from the nucleus
Bohrrsquos model worked well for the hydrogen atom but failed to explain the behavior of many other atoms
animated Bohr model
The amount of energy required to move from one energy level to the next
a quantum
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
3 James Chadwick (1891-1974)
Confirmed the existence of neutronsNeutrons are subatomic particles with no charge but with a mass equal to that of a proton
4 Ernest Rutherford (1871-1937)
Previously Thomsonrsquos model of the atom resembled chocolate cookie dough with the dough containing the protons and neutrons and the chocolate chips being the electrons
a The Gold Foil ExperimentSteps of the experiment(Figure 47)
1 Released positively charged alpha particles from a radioactive source towards a very thin sheet of gold foil
2 the beam of particles struck the gold foil
a The Gold Foil Experiment
Results
1 Most of the particles went straight through the foil
2 Some of the particles were deflected to the side
3 Some of the particles reflected directly back at the source
animation of experiment
1The atom is mostly empty space where the electrons are located (1)
2The atom has a nucleus which is a tiny dense central core (2)
3The nucleus is positive containing the protons and neutrons (3)
Conclusions
Based of the results from his experiment Rutherford developed the following theory of the atom
b Rutherfordrsquos Atomic Model
Bohr modified Rutherfordrsquos model to include newer discoveries about how the energy of an atom changes Bohr proposed that an electron is found only in specific circular paths or orbits around the nucleus
Bohr said that each possible electron orbit had fixed energy and these fixed energies of an electron are called energy levels
5 Niels Bohr model (1913)
The fixed energy levels are much like the rungs on a ladder and an electron cannot exist between these energy levels For an electron to move to another energy level they have to gain the correct amount of energy
The energy levels are not equally spaced and are closer together the further the electron gets from the nucleus
Bohrrsquos model worked well for the hydrogen atom but failed to explain the behavior of many other atoms
animated Bohr model
The amount of energy required to move from one energy level to the next
a quantum
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
4 Ernest Rutherford (1871-1937)
Previously Thomsonrsquos model of the atom resembled chocolate cookie dough with the dough containing the protons and neutrons and the chocolate chips being the electrons
a The Gold Foil ExperimentSteps of the experiment(Figure 47)
1 Released positively charged alpha particles from a radioactive source towards a very thin sheet of gold foil
2 the beam of particles struck the gold foil
a The Gold Foil Experiment
Results
1 Most of the particles went straight through the foil
2 Some of the particles were deflected to the side
3 Some of the particles reflected directly back at the source
animation of experiment
1The atom is mostly empty space where the electrons are located (1)
2The atom has a nucleus which is a tiny dense central core (2)
3The nucleus is positive containing the protons and neutrons (3)
Conclusions
Based of the results from his experiment Rutherford developed the following theory of the atom
b Rutherfordrsquos Atomic Model
Bohr modified Rutherfordrsquos model to include newer discoveries about how the energy of an atom changes Bohr proposed that an electron is found only in specific circular paths or orbits around the nucleus
Bohr said that each possible electron orbit had fixed energy and these fixed energies of an electron are called energy levels
5 Niels Bohr model (1913)
The fixed energy levels are much like the rungs on a ladder and an electron cannot exist between these energy levels For an electron to move to another energy level they have to gain the correct amount of energy
The energy levels are not equally spaced and are closer together the further the electron gets from the nucleus
Bohrrsquos model worked well for the hydrogen atom but failed to explain the behavior of many other atoms
animated Bohr model
The amount of energy required to move from one energy level to the next
a quantum
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
a The Gold Foil Experiment
Results
1 Most of the particles went straight through the foil
2 Some of the particles were deflected to the side
3 Some of the particles reflected directly back at the source
animation of experiment
1The atom is mostly empty space where the electrons are located (1)
2The atom has a nucleus which is a tiny dense central core (2)
3The nucleus is positive containing the protons and neutrons (3)
Conclusions
Based of the results from his experiment Rutherford developed the following theory of the atom
b Rutherfordrsquos Atomic Model
Bohr modified Rutherfordrsquos model to include newer discoveries about how the energy of an atom changes Bohr proposed that an electron is found only in specific circular paths or orbits around the nucleus
Bohr said that each possible electron orbit had fixed energy and these fixed energies of an electron are called energy levels
5 Niels Bohr model (1913)
The fixed energy levels are much like the rungs on a ladder and an electron cannot exist between these energy levels For an electron to move to another energy level they have to gain the correct amount of energy
The energy levels are not equally spaced and are closer together the further the electron gets from the nucleus
Bohrrsquos model worked well for the hydrogen atom but failed to explain the behavior of many other atoms
animated Bohr model
The amount of energy required to move from one energy level to the next
a quantum
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
1The atom is mostly empty space where the electrons are located (1)
2The atom has a nucleus which is a tiny dense central core (2)
3The nucleus is positive containing the protons and neutrons (3)
Conclusions
Based of the results from his experiment Rutherford developed the following theory of the atom
b Rutherfordrsquos Atomic Model
Bohr modified Rutherfordrsquos model to include newer discoveries about how the energy of an atom changes Bohr proposed that an electron is found only in specific circular paths or orbits around the nucleus
Bohr said that each possible electron orbit had fixed energy and these fixed energies of an electron are called energy levels
5 Niels Bohr model (1913)
The fixed energy levels are much like the rungs on a ladder and an electron cannot exist between these energy levels For an electron to move to another energy level they have to gain the correct amount of energy
The energy levels are not equally spaced and are closer together the further the electron gets from the nucleus
Bohrrsquos model worked well for the hydrogen atom but failed to explain the behavior of many other atoms
animated Bohr model
The amount of energy required to move from one energy level to the next
a quantum
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
Bohr modified Rutherfordrsquos model to include newer discoveries about how the energy of an atom changes Bohr proposed that an electron is found only in specific circular paths or orbits around the nucleus
Bohr said that each possible electron orbit had fixed energy and these fixed energies of an electron are called energy levels
5 Niels Bohr model (1913)
The fixed energy levels are much like the rungs on a ladder and an electron cannot exist between these energy levels For an electron to move to another energy level they have to gain the correct amount of energy
The energy levels are not equally spaced and are closer together the further the electron gets from the nucleus
Bohrrsquos model worked well for the hydrogen atom but failed to explain the behavior of many other atoms
animated Bohr model
The amount of energy required to move from one energy level to the next
a quantum
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
The fixed energy levels are much like the rungs on a ladder and an electron cannot exist between these energy levels For an electron to move to another energy level they have to gain the correct amount of energy
The energy levels are not equally spaced and are closer together the further the electron gets from the nucleus
Bohrrsquos model worked well for the hydrogen atom but failed to explain the behavior of many other atoms
animated Bohr model
The amount of energy required to move from one energy level to the next
a quantum
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
6 Schroumldinger (1926)
He proposed a mathematical equation to describe the behavior of electrons in atoms From his research the Quantum Mechanical Model was proposed
a atomic orbital
These are the regions of space (fuzzy clouds) that describe the probability of finding an electron
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
C Atomic Terminology
1Atomic NumberThe number of protons in the nucleus of an atom for a particular element (Table 42) It is also the number of electrons in a neutral atom
The number of protons identifies the element
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
The sum of the protons plus the neutrons in the nucleusMost of the mass of an atom is in the nucleusneutrons = Mass - atomic
Short hand for a particular atom
197 gold- 19779
Au
2Mass Number
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
3 Isotopes Atoms of the same element that are chemically alike but differ in their number of neutrons and mass
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
1Atomic mass
a atomic mass unit (amu)
Weighted average mass of all the isotopes for a particular element
1amu = 112 the mass of a carbon -12 atom1proton = 1amu1 neutron = 1 amu
The mass of an electron is negligible in comparison
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
To calculate the atomic mass you will need1 of isotopes2mass of the isotopes3 natural abundance of each isotope in decimal form
Atomic Mass = (mass abundance) + (mass abundance ) + helliphellip
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
5 Periodic Table
a Period
b Group
An arrangement of elements into groups based on their chemical properties
Horizontal rows 7 periods patterns of properties repeat from one period to the next
Vertical column elements within a group have similar chemical properties
