Ch 11 Introduction to Atoms. The Beginning of Atomic Theory Democritus & Aristotle Can you cut a...
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Ch 11 Introduction to Atoms. The Beginning of Atomic Theory Democritus & Aristotle Can you cut a piece of paper in half and cut those halves in half and
The Beginning of Atomic Theory Democritus & Aristotle Can
you cut a piece of paper in half and cut those halves in half and
continue until you are left with 1 particle? If you could do this
you would end up with what Democritus called an _________=
______________________ Aristotle _____________ with democrituss
idea. He believed that ___________________________________ Who was
correct? Aristotle or Democritus??
Slide 3
The Beginning of Atomic Theory ____________________was correct!
Matter is made of particles which we call ___________. Atom -
Slide 4
The Beginning of Atomic Theory Dalton 1803 Daltons atomic
theory was based on _________________! All substances are made of
______ Atoms are small particles that cannot be _____, _______, or
_________. Atoms of the same element are _________ and atoms of
different elements are _________. Atoms join with other atoms to
make _____ substances.
Slide 5
The Beginning of Atomic Theory New information didnt quite fit
with _______ ideas. His atomic theory had to be _________. Thomson-
1897 Discovered the ____________ charged particles There are
__________ inside the atom. Atoms can be broken down further.
(Dalton thought atoms were solid spheres so hes wrong)
Slide 6
CATHODE-RAY TUBE A positively charged plate was attracted to a
______. Therefore, the beam must be made up of ________ charges.
Thomson concluded these negative charges are _______ in every kind
of _______.
Slide 7
The Beginning of Atomic Theory ________- A subatomic particle
that has a negative charge. Thomson described his model of the atom
like plum pudding. Today you might call it the ______________ _____
model. (with electrons represented by _________________.)
Slide 8
The Beginning of Atomic Theory Rutherford- 1909 Rutherford was
a _____________ of Thomsons. He tried to help prove Thomson theory
was _______ and ended up proving him ______! He aimed a beam of
small, _________________ ( particles) at a thin piece of gold foil.
Photo paper behind the gold recorded where the charged particles
hit. Surprising Results He thought the particles would
_______________ the gold in a straight line. Some particles were
________. Some shot right ______.
Slide 9
Rutherfords Gold-Foil Experiment Rutherford determined an atom
must be mostly ______ ______ with a tiny part made of highly dense
material.
Slide 10
Rutherfords Model ________ The centrally located, tiny,
extremely dense positively charged part of an atom.
Slide 11
The Beginning of Atomic Theory Bohr 1913 Niels Bohr proposed
that electrons move around the nucleus in
_______________________________. Electrons can jump from path to
path but cannot exist in _____________ paths. Think of ________ on
a ladder. You can stand on the rungs, but not ________ the rungs.
Or think of planets in our solar system they do not stray off the
set path or ___________.
Slide 12
The Modern Atomic Theory Schr dinger and Heisenberg Electrons
________ travel in definite paths as Bohr suggested. The exact path
of the electron ______ be predicted. There are regions where it is
likely to be found called ______ __________.
Slide 13
4.2 The Atom How small is an _____? A penny contains __________
atoms. (20,000,000,000,000,000,000,000 atoms) An atom is made up of
_______, _______, and _________. The Nucleus Protons The mass of
protons are measured in atomic mass units (amu). Each proton has a
mass of __________ _________- Particles in the nucleus that have
___ electrical charge. Neutrons have a mass of 1 amu. (Same as
_________)
Slide 14
The Atom Outside the nucleus _________ are found outside the
nucleus. They have a _______ charge. They have a mass of almost
_____. If the number of protons __________ the number of electrons,
the atom is ______________
Slide 15
HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? Atoms of different
elements have different numbers of ____________. No two elements
have the same _____________. Atomic number is the number of
________ in an atom. All atoms of the _____________ have the
_________ atomic number.
Slide 16
HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? So how do we figure
out the number of neutrons for an atom? The number of _____________
= the number of _______________ Mass number The mass number does
not include the mass of ____________ because they are so
___________and have very little effect.
Slide 17
HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? Where do you find
these numbers? On the ____________________ ! C C C # of neutrons =
_________ - _________ # of neutrons in C = ____ - ____ C P + = N o
= E - = ______ # __ + # __ # __ ___
Slide 18
HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? Mass #Atomic
#ProtonsNeutronsElectrons Li Be B C N O F Na k
Slide 19
DRAWING BOHR MODELS OF ATOMS Draw the nucleus and label with #p
& #n Draw electron orbitals 1 st orbital can have ______
electrons only 2 nd and 3 rd ring can each have ______electrons
Fill _____________________ Inner rings must be filled first before
any electron enters a higher ring!!!!! Examples:
Slide 20
Changing Atoms If you change a persons hair color does it
change who they are? Weight? What subatomic particle determines an
atoms identity?___________ Therefore, the number of electrons and
neutrons can change in the atom and it is still the same atom. If
the number of protons __________ the number of electrons, the atom
is ______________ If the number of protons ___________ the number
of electrons, the atom becomes charged and we call it an _______.
Positively charged ions Negatively charged ions -
Slide 21
ISOTOPES _________- Atoms that have the same number of protons,
but have different numbers of neutrons. Examples: Hydrogen -1 and
Hydrogen -2 Naming Isotopes Write the __________ of the element,
followed by a hyphened and the _____________________ of the
isotope. Ex. A hydrogen atom with 1 proton and 0 neutrons A
hydrogen atom with 1 proton and 1 neutron
Slide 22
ISOTOPES Mass Number The sum of the _________________ in an
atom. (__________ are not included.) Mass # = protons + neutrons
Atomic Mass The _____________ of the masses of all the ___________
occurring isotopes of that element.
Slide 23
Solving the Atomic Mass Ex: Skittles consist of Orange 1 which
is 25% of the Skittles and Red 2 which is 75% of skittles. Step1:
change percents to decimals. Step 2: multiply the decimal by the
mass Step 3: add the two answers together
Slide 24
Solving for Atomic Mass Ex: Chlorine-35 which is 76% of the
Chlorine atoms and Chlorine-37 which is 24% of Chlorine atoms.
Step1: change percents to decimals. Step 2: multiply the decimal by
the mass Step 3: add the two answers together
