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Chemistry 11 – Unit 5 Forero
Name: ______________________________ Date: ___________ Blk: _____
NOTES: ATOMIC STRUCTURE
I. History of the Atom
Dalton
1803
Thomson
1897
Rutherford
1909
Bohr
1913
1. DALTON
2. THOMSON
- everything is made of _______________
- discovery of _______________ particle
(_____________)
- different______________ combine to
form ______________ in simple whole
______________
Cathode ray experiment
- rays are ____________, not __________
- each element has its own unique type of
___________ with a characteristic
___________
- new particles are ______________,
lighter than smallest atom
(_____________)
- ____________________________ model
- ____________________________model
3. RUTHERFORD
Thin gold foil experiment
- ______________ particles mostly pass through ______________
- but sometimes ______________ back when they hit something ______________
- thus, atom made mostly of ______________
- core of ______________ charged material, where most of the ______________ of the
atom is (______________)
- why don’t negative electrons give in to the pull of the positive nucleus and
______________ inwards?
Chemistry 11 – Unit 5 Forero
4. BOHR
- negatively charged electrons found in ________________________________________
around the positive charged nucleus
- electrons found at fixed ____________________ orbiting at fixed _________________
from the nucleus
- path closest to nucleus = ___________________________________
- energy ______________ the farther the orbits are from the nucleus
- the farther the electron is from the nucleus, the ______________ attraction it feels
- electrons can jump from one energy level to another, but are not found
______________ levels
- they lose or gain a discrete package of energy (____________________________)
every time it jumps levels  ____________________________
- explains why each element has a certain number of electrons available for
______________
- the electrons found on the ____________________________ ___________________
- planetary model
II. Atomic Number and Atomic Mass (review!)
Particles which make up the atom are called ______________.
1. Protons: ______________________________________________________________
2. Electrons: _____________________________________________________________
3. Neutrons: _____________________________________________________________
PARTICLE
The Properties of the Atomic Particles
SYMBOL
CHARGE
MOLAR MASS
LOCATION
Chemistry 11 – Unit 5 Forero
The chemical elements are different from one another by the number of ______________
in the nucleus.
ATOMIC NUMBER = ___________________________________________________
- found on top of ____________________________
A ______________ atom has ____________________________:
____________________________= ____________________________
EXAMPLE:
1. Any atom containing 3 protons must be…?
2. A neutral sodium atom has ___________ electrons
If ______________ are added to or subtracted from a neutral atom, the resulting particle
is called:
ION  # of protons ______ # of electrons
Electrons have a ______________ charge so:
- ______________ a______________ charge produces a ______________ion
- ______________ = # of e-______# of p’s
- ______________ a ______________ charge produces a ______________ ion
- ______________ = # of e- ______ # of p’s
Example:
1. If an electron is added to a neutral F atom, then the ion is written as:
2. If two electrons are removed from a neutral Ba atom, then the ion is written as:
Chemistry 11 – Unit 5 Forero
Since both neutrons and protons have a molar mass of approximately ______, then:
- Total mass of an atom = __________________________________________________
*the ______________ are too ______________ to make an appreciable contribution to
the mass of an atom
ATOMIC MASS = __________________________________, thus:
NUMBER OF NEUTRONS = _______________________ – ______________________
Example: Find the number of protons, neutron and electrons in the following atoms:
a) Al
b) C
But, then why is it that the atomic mass of some elements is not a whole number?
*See Titanium above…
III. Natural Mixtures: Isotopes and Mass Number
Example: ISOTOPES OF HYDROGEN
What’s the difference between Hydrogen-1, Hydrogen-2 and Hydrogen-3?
ISOTOPES: different ______________ of the same ______________, with the
_____________ # of protons but with _____________ #’s of neutrons, or…
- atomic species having the same ____________________________, but
different ____________________________
Chemistry 11 – Unit 5 Forero
MASS NUMBER = _______________________________________________________
____________________________________________________
Hydrogen-3
To find the p’s and n’s from nuclear notation:
Calcium-41
Find the # of protons and # of neutrons in each of the following isotopes:
Chemistry 11 – Unit 5 Forero
Now try the other way!
Now try it with ions! Find the same items on the table:
1)
56Fe3+
2)
76As3-
3)
201Au+
4)
82Br -
Chemistry 11 – Unit 5 Forero
EXTRA PRACTICE:
Write the nuclear notation:
1) An isotope has 46 protons, 58 neutrons and 42 electrons.
2) An isotope has 52 protons, 79 neutrons and 54 electrons.
NATURAL MIXTURES
- The molar mass of chlorine is 35.5 g. Since there can’t be 0.5 of a proton or neutron, then
this atomic mass __________ represent an ______________value of a ______________
of isotopes.
Example:
Find the average atomic mass of:
1) Cl, given that it is composed of 75.77% Cl-35 and 24.23% Cl-37.
2) B, given that it is composed of 18.8% B-10 and 81.2% B-11.
BONUS:
3) Naturally occurring silicon consists of 92.23% Si-28 (mass = 27.976927 g), 4.76%
Si-29 (mass = 28.976495 g) and 3.10% Si-30 (mass = 29.973770 g). What is the
expected average molar mass (atomic mass) of a sample of natural silicon,
expressed to 4 decimal places?
(Ans: 28.0855 g)