Transcript 2 Ions with a

Write the electron
configuration for K and Br.
Circle the Valence Electrons
A John Modica Production
Ionic Compounds
• Because electrons are negatively charged…
– an atom becomes positively or negatively
charged as it loses or gains an electron,
respectively.
• Any atom or group of atoms with a net charge
(whether positive or negative) is called an
ion.
+2
• A positively charged ion is a cation
t
Mg
n n O-2
• A negatively charged ion is an anion.
Compounds are two or more
elements that are held together by
opposite charge attraction.
Magnesium-12
12 (+)
10 (-)
+2 Charge
Metal
Oxygen-8
Non-metal
8 (+)
10 (-)
-2 Charge
Ionic Formulas
• Ions combine in small, whole number
proportions so that the sum of oxidation
numbers will be zero!
• Electrons are transferred from the metal
to the non-metal
– The metal become a cation (+ charge)
• Why?
– The non-metal becomes an anion (- charge)
• Why?
Metals combine with non-metals
Metals loose electrons to non-metals
They attract because their charges are opposite.
Ionic Formulas
• These are called Binary Compounds
– The prefix “bi” meaning two
– Two elements bonding to form a compound
• The metal ion ALWAYS goes first,
followed by the non-metal ion
So what does this look like?
+2
Mg O
-2
Magnesium Oxide
So what does this look like?
+3
Al S
2
-2
3
Aluminum Sulfide
So what does this look like?
+1
-1
Na Cl
Sodium
Chloride
A.k.a. Table
Salt
Your Turn!
+1
Na F
-1
-1
+2
Ba Cl
+3
-1
Al Br
+1
-2
KO
+1
-2
Li S
Your Turn!
Na F
Ba Cl
2
Al Br
3
KO
2
Li S
2
Now let’s Kick it up a notch!
Polyatomic Ions
• A group of 2 or more atoms that act as a
single unit
• When a metal and a polyatomic ion bond
this forms a tertiary compound
– 3 or more elements reacting to form a
compound
POLYATOMIC IONS
Polyatomic ions are mostly made of two non-metals.
Ions with -1 charge
perbromate
BrO4-1
bromate
BrO3-1
bromite
BrO2-1
hypobromite
BrO-1
perchlorate
ClO4-1
chlorate
ClO3-1
chlorite
ClO2-1
hypochlorite
ClO-1
periodate
IO4-1
iodate
IO3-1
iodite
IO2-1
hypoiodite
IO-1
nitrate
nitrite
NO3-1
NO2-1
hydroxide
cyanide
OH-1
CN-1
acetate
C2H3O2-1
Permanganate MnO4-1
bicarbonate
HCO3-1
Ions with a -2 Charge
carbonate
CO3-2
sulfate
SO4-2
sulfite
chromate
dichromate
oxalate
SO3-2
CrO4-2
Cr2O7-2
C2O4-2
Ions with a -3 Charge
phosphate
PO4-3
phosphite
PO3-3
arsenate
AsO4-3
Ions with +1 charge
ammonium ion NH4+1
Yes, I can read your minds…
No you do not have to memorize these
polyatomic ions.
You will receive a chart with these
Obviously!!!
Tertiary Compounds
• Polyatomics ions react as one unit, so you
treat them the same when writing formulas
– Use the criss-cross method
+1
Na PO
3
-3
4
Sodium Phosphate
Tertiary Compounds
-2
+2
Mg(SO)
4
Magnesium Sulfate
Tertiary Compounds
+3
Al (NO)
2
2
-2
3
Aluminum Nitrite
Yeah, I’ve
got nothing.
Your Turn!
-2
+1
-1
+2
Na SO
Ba ClO
2
4
+3
Al PO
-3
4
+1
-1
K NO
2
+1
-2
Li SO
3
Your Turn!
Na SO
4
2
Ba (ClO )
2 2
Al (PO )
4
K NO
2
Li SO
2
3
How do we know the charge of
the elements?
Glad you asked!
Oxidation Numbers
(most common)
-2
-3
-4
+3
+2
+1
-1
0
1A
H 2A
Li
+1 +2
Be
Click on element to see its
oxidation number(s)
Na Mg
K
Ca Sc Ti
Rb Sr
+2 +3
Y
V
+2 +4 7A
3A 4A 5A 6A
8A
H
He
B
C
N
O
F
Ne
Al
Si
P
S
Cl
Ar
Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te
Ce Ba La Hf Ta W Re Os Ir
Pt Au Hg Tl
Pb
Bi
I
Xe
Po At Rn
Fr Ra Ac Rf Db Sg Rh Hs Mt
return
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa
U
Np Pu Am Cm Bk Cf Es Fm Md No Lr