Ionic Compounds

What if the charges aren't balanced in an ionic compound? How do you write it out?

- Na+ and S2- -You need to balance them out - Na2S (if you have two positive sodium ions it makes the overall equation neutral)

What is a variable charge ion?

-The charges of the transition metals and metals under the metal line in groups 3A-6A cannot be predicted by looking at the periodic table, and some of the elements have more than one ion they can form. -They always form cations

How does one predict the charge of the rest of the metals? (the transition metals and metals under the metal line in groups 3-6)

-These can't be predicted from the periodic table. -They always form cations (positive ions)

Prefix "per"

-add one oxygen atom -Iodate: IO3-1 -Periodate: IO4-1

Suffix "ate"

-most common; usually has 3-4 oxygen atoms -Carbonate: CO32- -Nitrate: NO3-

Suffix "ite"

-subtract one oxygen atom -Chlorate: CIO3- -Chlorite: CIO2-

Prefix "hypo"

-subtract two oxygen atoms -Hypochlorite: CIO-

What are the three exceptions to the naming of a variable charge ion?

1. Al3+:Aluminum always forms an ion with a positive three. 2. Zn2+:Zinc always forms an ion with a positive two. 3. Ag+: Silver always forms an ion with a positive one. -These elements only form these ions, and the name of the ion is just the name of the element. -We do not use roman numerals for these three

How do you write the formula of an ionic compound?

1. Write the cation first, and write the values of the charge of each ion as a subscript. - Ax+ , By- → AyBx 2. If the subscripts are easily divisible, then reduce x and y to the lowest possible whole numbers. 3. If either A or B is a polyatomic ion and the subscript is larger than 1, enclose the polyatomic ion in ( ).

How does one predict charges from the periodic table?

Group 1: 1 valence electron, lose one (+1) Group 2: 2 valence electrons, lose two (+2) Group 3: (+3) Group 4: These usually don't form ionic bonds; they form covalent or molecular bonds. Group5: (-3) Group 6: (-2) Group 7: (-1) Group 8: 0

What are ionic compounds made of?

Ionic compounds are formed when a metal from the left side of the periodic table reacts with one or more nonmetal from the right side

The is the name of a monatomic anion?

The name of monatomic anions is the same as the element except we add -ide to the end of the name.

What is the name of a monatomic cation?

The same as the element

What are molecular ions (or polyatomic ions)?

These are molecules that exist as ions (they have a charge)

What does an ionic compound need to be stable?

To be stable, ionic compounds must have equal amounts of + and - charge. They need a cation and an anion.

What is a monatomic ion?

When a single atom forms an ion

How do you write the name of a variable charge ion?

When naming these ions we write the name and then the charge by using roman numerals in ( ). -Cr2+ -Chromium (II) -Cr3+ -Chromium (III)

10

deca

2

di

7

hepta

6

hexa

1

mono

9

nona

8

octa

5

penta

4

tetra

3

tri