#1 Name the ions formed by these elements and classify themas anions or cations

a. selenium

b. barium

c. phosphorus

selenide -2anion

barium ion +2cation phosphide ion -3

anion

#2How many electrons were lost or gainedto form these ions?

a. Fe3+

b. O2-

c. Cu+

3 lost

2 gained

1 lost

#3Key concept: Explain how the charges of Group A metal and nonmetal ions are related to their positions in the periodic table.

Group A elements

The charge onthe group A metalsis just the group number. The chargeon the non-metalsis the group numberminus 8

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4 Key concept: How are the charges of sometransition metal ions determined?

By how many electrons they lose. This cansometimes be more than one number for a given transition metal.(example Cr2+ and Cr3+)

5 Key concept: What are the usual endingsfor the names of polyatomic ions?

-ite or -ate

examples:

#6 What are the charges on ions of Group 1A, Group 3A(aluminum), andGroup 5A?

#7 How does a polyatomic anion differfrom a monatomic anion?

Hydroxide OH-1

Hydrogen sulfate HSO4-1

Nitrite NO2-1

Nitrate NO3-1

Chloride Cl-1

Oxide O-2

Carbonate CO3-2

polyatomic anionshave more than one

atom, monatomicanions have only one atom

#8 Write the symbol for the ion of each element. Classify the ion as an anion ora cation, and name the ion.

a. potassium: K+ cation; potassium ion

c. tin (2 electrons lost): Sn2+ cation; tin (II)

b. oxygen: O2- anion; oxide ion

f. cobalt (3 electrons lost): Co3+ cation; cobalt (III)

e. beryllium: Be2+ cation; beryllium ion

d. bromine Br- anion bromide ion

#9 Write the symbol or formula (includingcharges) for each of the following ions.

a. ammonium ion NH41+

b. tin (II) ion Sn2+

c. chromate ion CrO42-

d. nitrate ion NO31-