Ionic Compounds from mono and polyatomic ions
Objective:
naming mono-atomic ions and the compounds they form,
and poly-atomic ions and the compounds they form.
FIRST...
sodium forms an ion, so does chlorine.
Write the atomic symbol, the ionic symbol,
and then see if you can figure out how
they combine into a NEUTRAL IONIC COMPOUND.
Chlorine is bigger, so chlorine
is the pink one in this picture.
Forming Ionic Compounds, the rules...
The sodium atom forms a cation, the
chlorine atom forms an anion.
The Na becomes Na+1.
The Cl becomes Cl–1.
The charges are equal and opposite,
so they will be able to
combine in a 1:1 ratio,
forming neutral NaCl,
which is sodium chloride
(table salt).
NaCl is sodium chloride.
Let’s look at how these names work.
• The cation always goes first.
• That means the anion has to go second.
• That is always true.
• The metal is always the cation.
You say the name of the metal atom just as it is.
• The anion here is chlorine. We’ll have to change that
name chlorine to chloride to be proper.
• The mono-atomic anions get an -ide name ending.
• Thus, NaCl is sodium chloride
(not sodium chlorine, or chlorine sodium, etc.)
Let’s try to name these four ionic compounds.
PLEASE NOTE,
the metals are always first,
the non-metals are always second.
All ionic compounds are made up of a |
METAL + NON-METAL
KCl -
LiBr MgO CsS -
All ionic compounds are made up of a |
METAL + NON-METAL
the metal atom name is the exact same as its
name as an atom, the anion gets the -ide ending.
KCl - potassium chloride
LiBr - lithium bromide
MgO - magnesium oxide
CsS - cesium sulfide
MgO forms,
just like in lab.
All ionic compounds are NEUTRAL
- even though they form from charged cations (+)
combining with charged anions (-).
The positive charges must equal the negative charges.
THINK, what if an ionic compound forms between
calcium and chlorine?
What are the ions, what is the compound called,
and what is the chemical formula for this?
CALCIUM + CHLORINE
Calcium Chloride
Calcium atom becomes calcium cation
Chlorine atom becomes chlorine anion
Ca + Cl yields
hey wait a second, the positives don’t equal the negatives!
Since calcium is a +2 cation, it would take two -1 anions to form a
NEUTRAL IONIC COMPOUND. That’s what happens!
Ca+2 + Cl-1 + Cl-1
CaCl2
and that is called calcium chloride, a neutral ionic compound
Now try to form these neutral ionically bonded
compounds from the following ions... copy this chart
into your notes now.
atom
atom
Na
S
Ca
O
Be
Br
Li
N
cation
anion
compound
formula
compound
name
Let’s see how well you did, we’ll check the ions first
then we’ll finish up on the next slide.
atom
atom
cation
anion
Na
S
Na+1
S-2
Ca
O
Ca+2
O-2
Be
Br
Be+2
Br-1
Li
N
Li+1
N-3
compound
formula
compound
name
And now for the rest of the story.
Hang in there, we’re learning SO much today!
atom
atom
cation
anion
compound
formula
Na
S
Na+1
S-2
Na2S
Ca
O
Ca+2
O-2
CaO
Be
Br
Be+2
Br-1
BeBr
Li
N
Li+1
N-3
LiN3
compound
name
And now for the rest of the story.
Hang in there, we’re learning SO much today!
atom
atom
cation
anion
compound
formula
compound
name
Na
S
Na+1
S-2
Na2S
sodium
sulfide
Ca
O
Ca+2
O-2
CaO
calcium
oxide
Be
Br
Be+2
Br-1
BeBr
beryllium
bromide
Li
N
Li+1
N-3
LiN3
lithium
nitride
And now you’re smarter than you ever imagined! Time to
put you to the test. Get ready, keep your thinking hats
on!
Here are your atoms,
determine how to form proper
cations and proper anions,
and make NEUTRAL IONIC
COMPOUNDS. Make sure
your positives always equal
your negatives! Good Luck!
• aluminum plus oxygen
• aluminum plus chlorine
• magnesium plus nitrogen
• potassium plus calcium
• aluminum plus oxygen
• aluminum plus chlorine
• magnesium plus nitrogen
• potassium plus calcium
cation anion
make sure that the positives
are equal to the negatives to
form NEUTRAL IONIC
compounds. The cations
come first, the anions
second, with the -ide ending
names.
formula
name
Al+3
O-2
Al2O3
aluminum oxide
Al+3
Cl-1
AlCl3
aluminum chloride
Mg+2
N-3
Mg3N2
magnesium nitride
K+1
Ca+2
???
no such thing, two cations
can never combine
???
Chemistry keeps getting more real, here
comes some more really great stuff. Take
out page one of your reference tables.
Check out TABLE
E
Talk to your neighbor, what’s this table all about?
We’re psyched!
We learned this stuff
from Charlie Arbuiso
a long time ago and
now we’re studying
chemistry in the
wild!
Table E lists a bunch of ions that are formed
when a few atoms combine together but act as a
unit. They are given to you and you will not
have to memorize them. Remember where this
Table E is though, you’ll need it a lot!
POLY means many
ATOMIC means about atoms
IONS means charged atoms (positive or negative)
THEY ACT AS A UNIT, that’s the important part!
Let’s combine a few cations and anions from the Periodic
Table as well as Table E. The easy part is that there is
NO RULE for polyatomic ion naming, they keep the
names that they have on the table E.
Less thinking = more time for FUN.
cation
anion
Na+1
OH-1
Mg+2
SO4-2
Ca+2
C2O4-2
NH4+1
Cl-1
compound
name
Let’s see how you did here.
compounds first, then next slide for the names
Be sure to note that the compounds are ALL NEUTRAL.
cation
anion
compound
Na+1
OH-1
NaOH
Mg+2
SO4-2
MgSO4
Ca+2
C2O4-2
CaC2O4
NH4+1
Cl-1
NH4Cl
name
Let’s see how you did here.
compounds first, then next slide for the names
Be sure to note that the compounds are ALL NEUTRAL.
cation
anion
compound
name
Na+1
OH-1
NaOH
sodium hydroxide
Mg+2
SO4-2
MgSO4
magnesium sulfate
Ca+2
C2O4-2
CaC2O4
calcium oxalate
NH4+1
Cl-1
NH4Cl
ammonium chloride
This is hard stuff. You are smart kids. We will
practice this until it’s like tying your shoes or riding
a bicycle, or even, like walking around your own
house in the dark.
It’s hard, you’re new at it, relax. Does your teacher
look nervous? No, so you shouldn’t be either.