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2.1 – Atoms, Ions, and Molecules
Do Now:
In terms of chemistry, what do a frog, a skyscraper, and your body all have in common?
Atoms
Atom- smallest basic unit of matter
It would take more than 1 trillion years to count the atoms in a single grain of sand
H
O
Hydrogen atom (H)
Oxygen atom (O)
Subatomic Particles
Atoms are made up of 3 smaller parts:
1. Protons (+) – Found in nucleus
2. Neutrons (0) – Found in nucleus
3. Electrons (-) – Energy levels outside of nucleus
Oxygen atom (O)
Nucleus:8 protons (+)8 neutrons
outermost energy level: 6 electrons (-)
inner energy level: 2 electrons (-)
Elements
Element- one particular type of atom, cannot be broken down
If all elements are made up of atoms… what distinguishes between elements?
Reading the periodic table:
Elements in living things
“CHNOPS”
Carbon, Hydrogen, Oxyen, and Nitrogen make up about 95% of our body
Sulfur is needed for proteinsPhosphorous is needed for DNAYou must memorize these!!!!!
Compound
Compound- a substance made of atoms of different elements bonded together in a certain ratio
A compound has different properties than the elements that it is made of
What type of chemical compounds have we talked about so far this year?
OHH
_
++
Carbon Dioxide
Example:
Hydrogen and Oxygen are both found as gases naturally on earth
BUT… when combined they can form water
A diamond is pure carbon but carbon atoms are also found in sugar, protein, and millions of other compounds.
Quick review:
How are elements different from compounds?
Give at least 2 reasons:
Ions form when atoms gain or lose electrons.
An ion is an atom that has gained or lost one or more electrons. positive ions
negative ions
• Ionic bonds form between oppositely charged ions. They are held together by electrical force!
• Easily dissolve in water!
Sodium atom (Na) Chlorine atom (CI) Sodium ion (Na+) Chloride ion (CI-)
Na loses anelectron to CI ionic bond
gained electron
Ionic Bond Example:
How do we know if an atom wants to gain or lose electrons?
The atom wants a full energy level by moving the LEAST amount of electrons So…
If it has 3 or less electrons it will give electrons away and become POSITIVELY charged
If it has 5 or more electrons it will gain more electrons and become NEGATIVELY charged
Atoms share pairs of electrons in covalent bonds.
A covalent bond forms when atoms share a pair of electrons.
Usually very strong! covalent bonds
Oxygen atom (O) Carbon atom (C) Oxygen atom (O)
Carbon dioxide (CO2 )
– multiple covalent bonds– diatomic molecules
– Ex: O2
Molecules
Molecule- two or more atoms held together by covalent bonds
One last type of bonding – Dipole-Dipole
Due to the unequal sharing of electrons, some molecules have a slightly positive and a slightly negative end to them, or a dipole (di-pole = two magnetic poles)
These compounds can form weak bonds with one another without combining together completely to create new compounds
Ex: Water hydrogen bonds Van Der Waals forces
Isotopes
Isotope: An atom that contains a larger or smaller number of neutrons than usual
-similar chemical properties
-still no charge
Student ntoes
2.1 – Atoms, Ions, and Molecules
Atoms
Atom- ______________________________
It would take more than 1 trillion years to count the atoms in a single grain of sand
H
O
______________ Particles
Atoms are made up of 3 smaller parts:
1. _____________(+) – Found in ______________
2. ____________(0) – Found in _______________
3. ______________(-) – Energy levels outside of nucleus
Oxygen atom (O)
Nucleus:8 protons (+)8 neutrons
outermost energy level: 6 electrons (-)
inner energy level: 2 electrons (-)
____________________
Element- one ____________________________, cannot be broken down
If all elements are made up of atoms… what distinguishes between elements?
Reading the periodic table:
Elements in living things
“___________________”
____________, ______________, ___________, and ____________make up about 95% of our body
Sulfur is needed for proteinsPhosphorous is needed for DNAYou must memorize these!!!!!
__________________
Compound- a substance made of ________________________________________________________________________
A compound has _______________________than the elements that it is made of
What type of chemical compounds have we talked about so far this year?
OHH
_
++
Example:
Hydrogen and Oxygen are both found as gases naturally on earth
BUT… when combined they can form water
A diamond is pure carbon but carbon atoms are also found in sugar, protein, and millions of other compounds.
Quick review:
How are elements different from compounds?
Give at least 2 reasons:
Ions form when atoms _____________________________
An _________________is an atom that has gained or lost one or more electrons. _______________ions
________________ions
• ______________________form between oppositely charged ions. They are held together by electrical force!
• ______________________________!
Sodium atom (Na) Chlorine atom (CI) Sodium ion (Na+) Chloride ion (CI-)
Na loses anelectron to CI ionic bond
gained electron
Ionic Bond Example:
How do we know if an atom wants to gain or lose electrons?
The atom wants _______________________ by moving the ___________amount of electrons
So… If it has 3 or less electrons it will give electrons away and become POSITIVELY charged
If it has 5 or more electrons it will gain more electrons and become NEGATIVELY charged
Atoms share pairs of electrons in covalent bonds.
A ________________________ forms when atoms share a pair of electrons.
Usually __________________! covalent bonds
Oxygen atom (O) Carbon atom (C) Oxygen atom (O)
Carbon dioxide (CO2 )
– multiple covalent bonds– diatomic molecules
– Ex: O2
Molecules
__________________- two or more atoms held together by _____________________
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