• Protons are in the nucleus
(center) of the atom
• Have a positive charge
• Neutrons are in the nucleus
(center) of the atom
• Are neutral; have no charge
• Electrons move in energy
levels outside of the nucleus
• Have a negative charge
• Nucleus contains both
protons and neutrons and
most of the atoms mass
• Have a positive charge
http://jchemed.chem.wisc.edu/JCESoft/CCA/pirelli/pages/cca3NI3.html
The columns are called groups or families. Groups have similar physical and
chemical properties and the same number of valence electrons
Name the groups boxed in yellow, orange, green and blue.
The rows are called periods. They tell you how many energy levels an atom has
What is the energy level of Nickel, Ni?
What is the principle energy level of Nickel, Ni? 4—it is in the row numbered 4
8th Grade SOL Review—Atomic Structure
Using the SOL Periodic Table
Click on the link to get the SOL periodic table
Keep this Adobe file open as you work on the review
Let’s use the periodic table to answer some questions about
Silicon
8th Grade SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have?
8th grade SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have?
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have? 14 electrons (#
electrons = # protons in neutral atoms)
How many neutrons does Silicon-30 have?
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have? 14 electrons (#
electrons = # protons in neutral atoms)
How many neutrons does Silicon-30 have? 16 neutrons. Silicon-30 is
an isotope of Silicon. It has a mass number of 30. The mass number is
protons + neutrons.
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have? 14 electrons (#
electrons = # protons in neutral atoms)
How many neutrons does Silicon-30 have? 16 neutrons. Silicon-30 is
an isotope of Silicon. It has a mass number of 30. The mass number is
protons + neutrons.
What is the atomic mass of Silicon?
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have? 14 electrons (#
electrons = # protons in neutral atoms)
How many neutrons does Silicon-30 have? 30 neutrons. Silicon-30 is
an isotope of Silicon. It has a mass number of 30. The mass number is
protons + neutrons.
What is the atomic mass of Silicon? 28.0855 grams/mole (this is the
same as the atomic mass on the periodic table)
8th grade SOL Review—Atomic Structure
What are Valence electrons?
# Valence = Group Number for Groups 1 & 2
for Groups 13-18 subtract 10
Chemistry SOL Review—Atomic Structure
Valence electron configuration and the periodic table
How many valence electrons
does Lithium have? (Group 1)
Chemistry SOL Review—Atomic Structure
Valence electron configuration and the periodic table
How many valence electrons
would Boron have? (Group 13)
Chemistry SOL Review—Atomic Structure
Isotopes: elements with the same number of protons, but a different
number of neutrons.
12
C
6
13
C
6
Carbon-14 has ___ protons and ___ neutrons
14
C
6
Chemistry SOL Review—Atomic Structure
Isotopes: elements with the
same mass, the same number
of protons, but a different
number of neutrons.
12
C
6
13
C
6
14
C
6
Chemistry SOL Review—Atomic Structure
Isotopes: elements with the same number of protons, but a different
number of neutrons.
12
C
6
13
C
6
Carbon-12 has 6 protons and 6 neutrons
Carbon-13 has 6 protons and 7 neutrons
Carbon 14 has 6 protons and 8 neutrons
14
C
6
Chemistry SOL Review—Atomic Structure
Development of the Atomic
Model
Thompson Model
 Rutherford Gold Foil
Experiment and Model
 Bohr Model
 Quantum-Mechanical
Model

The problems of language here are really serious. We wish to speak
in some way about the structure of the atoms. But we cannot speak
about atoms in ordinary language.
Heisenberg
Chemistry SOL Review—Atomic Structure
Thompson Model

The atom is a positively charged diffuse
mass with negatively charged electrons
stuck in it.
From Mark Rosengarten’s New York Regent’s Powerpoint
Chemistry SOL Review—Atomic Structure
Rutherford Model

The atom is made of a small, dense, positively
charged nucleus with electrons at a distance, the vast
majority of the volume of the atom is empty space.
Alpha particles shot
at a thin sheet of gold
foil: most go through
(empty space). Some
deflect or bounce off
(small + charged
nucleus).
From Mark Rosengarten’s New York Regent’s Powerpoint
Chemistry SOL Review—Atomic Structure
Bohr Model

Electrons orbit around the nucleus in energy levels
(shells). Atomic bright-line spectra was the clue.
From Mark Rosengarten’s New York Regent’s Powerpoint
8th Grade SOL Review—Atomic Structure
Electron Cloud Model
Electron energy levels are wave functions.
 Electrons are found in orbitals, regions of space
where an electron is most likely to be found.
 You can’t know both where the electron is and where
it is going at the same time.
 Electrons buzz around the nucleus like gnats buzzing
around your head.

From Mark Rosengarten’s New York Regent’s Powerpoint