1. Ions

2. Remember: Atoms make elements Elements make compounds
Everything around you is made of compounds
What that compound does, depends on how the elements inside are bonded

3. At this point…
We know an atom has +ve protons in the nucleus and –ve electrons outside the nucleus
Normally the two are equal so this makes the atom neutral
What would happen if the protons and electrons were not equal?

4. Ion A charged atom or group of atoms
When we take away or add electrons to an atom, we disrupt the balance.
There is now more/less e- than p+
Ions are never formed by changing the # of protons!

5. Positive or Negative? Lose an electron = Positive ion
Lose weight = good thing
Called a “cation”
Cats are cute!

6. Positive or Negative? Gain an electron = Negative ion
Gain weight = bad thing
Called an “anion”
Unlikable words start with “an”:
analogy
anaconda
anarchy
anchovy
anger
anguish
animosity
annihilate

7. Let’s look at an example
Sodium – Na
In group 1A, so it has one valence e-
If we take that one valence e- away, the sodium atom will have “lost weight”
It will be positive Na+

8. Another example Fluorine F
If we add an e-, fluorine has “gained weight”
F -

9. What do we call them? Cations Anions Named after the “parent” atom
Na+ atom would be called a sodium ion
Mg+2 atom: called a magnesium ion
Al+3 atom: called an aluminum ion
Anions
Named by taking the root of the atom name and changing the ending to -ide
Cl- atom: called chloride ion
O-2 atom: called oxide ion

10. Ions and the Periodic Table
The cation atoms match their group number in the first 3 groups
Li+1 is in Group 1A
Sr+2 is in Group 2A
Ga+3 is in Group 3A
Transition metals will form multiple positive ions depending on what they are mixing with

11. Metals always lose their e- so they will always have +ve ions
Nonmetals always gain e- so they will always have –ve ions
Group 6 atoms have a -2 charge
Group 7 atoms have a -1 charge

12. Chemical Bonds
A chemical bond is the force needed to hold two atoms together
This bond can come from an attraction between a +ve nucleus and -ve e-
Bond could come from attraction of positive and negative ions

13. Any way you look at it, a chemical bond forms because of “opposite attraction”
Lets look at some examples…

14. Opposites Attract

15. Opposites Attract

16. Opposites Attract

17. Opposites Attract

18. Why are they attracted to each other?
Valence electrons of course!
Electron-dot-diagrams will help us to see this
Group 1A 2A 3A 4A 5A 6A 7A 8A
Diagram Li Be B C N O F Ne

19. What is an ionic bond?
Ionic bond is the force that holds oppositely charged particles together in an ionic compound

20. What’s in an ionic compound?
At least one cation and one anion have to be present

21. Talking about Ionic Compounds
When saying the compound or writing it down, you have to mention the cation 1st
If there are only 2 elements, we call it a binary compound

22. Solving Ionic Compounds
# of e- lost has to = # of e- gained
Na +
Cl 
Na+ +
Cl-

23. Let’s look at some examples!
if we add 3 Na atoms to fill all the N spots, we lose as much as we have gained
Na +
N  Na
Na +
N  Na
Na3N N Na

24. Li +
O  Li O Li
Li2O

25. Formula unit
The simplest ratio of ions in an ionic compound

26. Monatomic ion
A one-atom ion
Mg +2
Br -
Cs +

27. Oxidation Number The charge on a monatomic ion
Mg +2 charge = +2
Br - charge = -1
Cs + charge = +1
It is possible to have more than one oxidation #

28. Al+3, Ga+2, Ga+3, In+, In+2, Tl+, Tl+3
Oxidation Numbers
Group
Common Ions 3B
Sc+3, Y+3, La+3 4B
Ti+2, Ti+3 5B
V+2, V+3 6B
Cr+2, Cr+3 7B
Mn+2, Mn+3, Tc+2 8B
Fe+2, Fe+3
Co+2, Co+3
Ni+2, Pd+2, Pt+2, Pt+4 1B
Cu+, Cu+2, Ag+, Au+, Au+3 2B
Zn+2, Cd+2, Hg2+2, Hg+2 3A
Al+3, Ga+2, Ga+3, In+, In+2, Tl+, Tl+3 4A
Sn+2, Sn+4, Pb+2, Pb+4

29. Oxidation Numbers
When bonding 2 atoms together, their oxidation numbers have to equal zero Na
+ Cl
 Na+
+ Cl-
 NaCl

30. Polyatomic ions Ions made of more than one atom
Even though there are more than one element involved, we still consider it as one ion
You never change subscripts

31. Polyatomic Ions Ion Name NH4+ ammonium IO4- periodate NO2- nitrite
C2H3O2-
acetate
NO3-
nitrate
H2PO4-
dihydrogen phosphate
HSO4-
hydrogen sulfate
CO3-2
carbonate
OH-
hydroxide
SO3-2
sulfite
CN-
cyanide
SO4-2
sulfate
MnO4-
permanganate
S2O3-2
thiosulfate
HCO3-
hydrogen carbonate
O2-2
peroxide
ClO-
hypochlorite
CrO4-2
chromate
ClO2-
chlorite
Cr2O7-2
dichromate
ClO3-
chlorate
HPO4-2
hydrogen peroxide
ClO4-
perchlorate
PO4-3
phosphate
BrO3-
bromate
AsO4-3
arsenate
IO3-
iodate

32. Polyatomic Ions Sodium and Nitrate Calcium and chlorate Na+ + NO3-
+ ClO3-
 Ca(ClO3)2

33. Naming Ions and Ionic Compounds
When you have polyatomic ions with the same root element but different numbers of oxygen
NO3- and NO2-
The one with the most oxygen will be named after the root element with –ate on the end
The one with the least amount of oxygen will be named after the root element with –ite on the end
nitrate and nitrite

34. What would we call…
SO4-2 and SO3-2
sulfate and sulfite

35. One element - 4 combos
Greatest number of oxygen, named with prefix per- and suffix -ate
Next in line has the suffix –ate
Third in line has the suffix –ite
Lastly, it has the prefix hypo- and the suffix –ite
ClO4-
ClO3-
ClO2-
ClO-
perchlorate
chlorate
chlorite
hypochlorite

36. Naming Ionic Compounds
Name the cation 1st
Monatomic cations use the element name
Monatomic anions take their name from the root of the element name plus the suffix –ide
If the compound has a polyatomic ion, you simply name it

37. Examples NaBr name the cation 1st and use the cation name
Sodium
Add –ide to the root of the anion
Sodium bromide

38. Example:
Cu(NO3)2
Copper can have a +1 or +2 charge, how do we know which to choose?
Nitrate is only a -1 charge and there are 2 of them, so …
We must be using the +2 copper
Copper (II) nitrate