TOPIC: Ions
Do Now:
1. In a neutral atom, the # of Protons equals
the # of ___________
2. Mass Number = ____________________
3. The charge of the nucleus is always______
4. How do you calculate the number of
neutrons?
5. What is the overall charge of an ion that
has 12 protons, 10 electrons and
14 neutrons?_____________
• Atoms without charge are called
ATOMS
(they are neutral)
• Atoms with positive or negative
charge are called
IONS
WHEN REMOVING ELECTRONS
THE RESULTING CHARGE IS POSITIVE
neutral
1+
WHEN ADDING ELECTRONS
THE RESULTING CHARGE IS NEGATIVE
neutral
2
• Metals lose electrons – they become
positive ions
• Nonmetals gain electrons – they become
negative ions
WHO
CARES
ABOUT
IONS?!
• ions make up the salt you put on your
eggs in the morning - and many other
compounds
• Ions are important for your body (we
call them electrolytes
• Kidneys keep electrolyte
concentration in the blood
constant
• When you sweat you lose K+
and Na+
• So you drink sports drinks
• Important to carry electrical
impulses from the brain
• Nerve impulses
• Muscle contractions
As for your body, the
major electrolytes are
follows:
sodium (Na1+)
potassium (K1+)
chloride (Cl1-)
calcium (Ca2+)
magnesium (Mg2+)
bicarbonate (HCO3+)
phosphate (PO42-)
sulfate (SO42-)
1+
2-
3+
1-
Why?!?!?!?!?!?!
sodium (Na1+)
potassium (K1+)
chloride (Cl1-)
calcium (Ca2+)
magnesium (Mg2+)
bicarbonate (HCO3+)
sulfate (SO42-)
It has to do with valance
electrons!
Valence Electrons
• Chemical behavior determined by #
valence electrons
• Elements with same # valence electrons
will have similar chemical properties
–Elements in same
column have similar
chemical properties
Going Down Column 1:
Period
Element
Configuration
1
H
1
2
Li
2-1
3
Na
2-8-1
4
K
2-8-8-1
5
Rb
2-8-18-8-1
6
Cs
2-8-18-18-8-1
7
Fr
2-8-18-32-18-8-1
Electron configuration 2-7
Inner electrons (kernel electrons) = 2
Valance electrons = 7
When predicting how Fluorine (F) will react, all we care
about are the 7 valence electrons
Predicting Reactions
• Octet Rule: Everyone wants to be a noble gas. The noble
gases are PERFECT! They have a full outer shell
• (8 valance electrons)
• 2-8
• 2-8-8
• 2-8-18-8
• 2-8-18-18-8
• All elements must have a full outer shell in order to react, so
they either take or share valence electrons.
• Atoms are lazy (like you!) and they don’t want to do too much
work. If they have 1,2,or 3 valence electrons, they will lose them
rather than searching for 5,6,or 7 to fill their shell
• 1,2,3 valence electrons = lose
• 5,6,7 valence electrons = gain
• Remember 2 on the first shell is full
Let’s Practice
Element
Electron
Configuration
# of elost/gained
Charge
New e
Config
“Like” which
Noble Gas
1. Be
2-2
Lost 2
Be2+
2
He
2. Al
2-8-3
Lost 3
Al3+
2-8
Ne
3. S
2-8-6
Gain 2
S2-
2-8-8
Ar
4. Ba
2-8-18-18-8-2
Lost 2
Ba2+
2-8-18-18-8
5. Br
2-8-18-7
Gain 1
Br1-
2-8-18-8
Kr
6. Rb
2-8-18-8-1
Lost 1
Rb1+
2-8-18-8
Kr
Xe
Transition Metals