SCIENCE 9: Chemistry – Atomic Structure
1.
Terms:
Periodic Table
Atom
Proton
Electron
Neutron
Atomic Number
Atomic Weight
(Mass Number)
Ion
Bohr Diagram
2. How would you find out the number of ******** in an atom?
a)
Protons:
b)
Electrons:
c)
Neutrons:
i)
Examples:
Carbon: Atomic #=6
Mass #=12
Potassium: Atomic #=19 Mass #=39
ELEMENT
HYDROGEN
HELIUM
LITHIUM
BERYLLIUM
BORON
CARBON
NITROGEN
OXYGEN
FLUORINE
NEON
SODIUM
MAGNESIUM
ALUMINUM
SILICON
PHOSPHORUS
SULFUR
CHLORINE
ARGON
SYMBOL
# PROTONS
#NEUTRONS
#ELECTRONS
3. Bohr Diagrams:
a)
1st level = 2 electrons maximum
b)
2nd level = 8 electrons maximum
c)
3rd level = 8 electrons maximum
d)
A lower level must be FULL before electrons can be placed into a
higher level
Example:
Carbon: 6 electrons
Magnesium: 12 electrons
4. Ions:
a)
An atom may gain or lose electrons in order to “behave” like an atom
with a full outer level.
b)
Atoms that lose electrons become positive (+) ions
c)
Atoms that gain electrons become negative (-) electrons
Examples:
Magnesium:
 has 2 electrons in the third level
 loses 2 electrons to have a full second level
 12 protons (+) + 10 electrons (-) = +2 charge
Oxygen:
 has 6 electrons in the second level
 gains 2 electrons to have a full second level
 8 protons (+) + 10 electrons (-) = -2 charge
Atomic Structure Chart: Complete the missing information in the chart
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

ELEMENT
Atomic #
Mass #
Hydrogen
SYMBOL
#
PROTONS
#
ELECTRONS
#
NEUTRONS
8
8
8
BOHR
DIGRAM
POSSIBLE
ION
Na
Cl1-
Fluorine
S
15
15
16
Li1+