DO NOW:
1. Take out HW
2. In M.C. Packet
COMPLETE MULTIPLE
CHOICE QUESTIONS pg. 68 all Atomic Structure
questions
REGENTS REVIEW TOPIC 1 – THE ATOM
1. Modern model of the atom has evolved over a long period
of time through the work of many scientists
Dalton: (hard sphere)
o Elements are made of atoms
o Atoms of an elements are the same
o Compounds are formed from a
combination of atoms
REGENTS REVIEW TOPIC 1 – THE ATOM
Thomson
o Plum Pudding Model
Rutherford Experiment
oBombard gold foil with alpha particles
oAtoms are mostly empty space
With small dense positively charged nucleus
REGENTS REVIEW TOPIC 1 –
THE ATOM
Bohr Model:
o Small dense positively charged
nucleus surrounded by electrons
in circular orbit
Wave Mechanical Model
oSmall dense positively charged nucleus surrounded by an
electron cloud
o“Orbitals” – areas where an electron
with a certain amount of energy
is most likely to be found
REGENTS REVIEW TOPIC 1 – THE ATOM
2. Each atom is made of a positively charged nucleus
with one or more negatively charged electrons
3. Protons and neutrons are found in the nucleus
4. Protons have a positive charge
Neutrons have a neutral charge
Electrons have a negative charge
REGENTS REVIEW TOPIC 1 – THE ATOM
5. # of protons = # of electrons
- atom is neutral
6. Mass of proton - 1 amu
Mass of neutron – 1 amu
Mass of electron – negligible mass
Atomic mass of an atom = # protons + # neutrons
amu is = 1/12 mass of carbon atom
REGENTS REVIEW TOPIC 1 – THE ATOM
7. Each electron in an atom has its own distinct amount of energy
oAll electrons in lowest energy = ground state
oElectrons fill in energy levels and orbitals that requires the least
amount of energy and then move up to the next energy level
8. Electrons gain energy and move to higher orbitals – excited state
9. Electrons return from higher energy state to a lower energy state
oEmits energy in the form of light
oBright line spectrum
REGENTS REVIEW TOPIC 1 – THE ATOM
10.Outermost electrons – valence electrons
• Responsible for chemical properties
• Most elements max # of valence electrons = 8 (except H which
only has 2)
• Atoms form bonds to fill their valence shell
• Can use orbital notation or Lewis Dot Sructure to show the
configuration of the valence electrons
11. Atoms of the same element all contain the same number of
protons
• Changing the number of protons changes the atom into a
different element
• The atomic number = # of protons of an element
REGENTS REVIEW TOPIC 1 – THE ATOM
12.Isotopes are atoms with equal numbers of protons but
different number of neutrons
• Isotopes of an element have the same atomic number
but different atomic masses
13.The average atomic mass of an element is the
weighted average of its naturally occurring isotopes
The formula for calculating the average atomic mass is:
COMPLETE # 1-16
PG. 2 OF
HANDOUT