Polyatomic Ions

Question 1

Which polyatomics contain oxygen? What names do they end in? Which names do they begin with? Which of these polyatomics behave the same?

Answer 1

Oxyanions. Names end in -ate or -ite. -Ate is used for the most common form. -Ite is used for the form with the same charge, but one less oxygen.

Example: NO3 (charge = -1) = nitrate
NO2 (charge = -1) = nitrite

Per- indicates one more oxygen than the -ate form (“PERfect = overachieving”). Hypo- indicates one fewer oxygen than the -ite form.

Example: ClO4 (charge = -1) = perchlorate (one more O than -ate form)
ClO3 (charge = ^) = chlorate (most common form)
ClO2 (^) = chlorite (one less O than -ate form)
ClO (^) = hypochlorite (one less O than -ite form)

F, Cl, Br, and I all behave the same. Therefore, for example, if chlorate is ClO3 (charge = -1), the bromate ion is BrO3 (charge = -1).

Question 2

Acetate (2 ways to write it)

Answer 2

C2H3O2 (charge = -1) or CH3COO (charge = -1)

Question 3

Bromate

Answer 3

BrO3 (charge = -1)

Question 4

Chlorate

Answer 4

ClO3 (charge = -1)

Question 5

Chlorite

Answer 5

ClO2 (charge = -1)

Question 6

Cyanide

Answer 6

CN-

Question 7

Hydrogen carbonate or Bicarbonate

Answer 7

HCO3 (charge = -1)

Question 8

Hydroxide

Answer 8

OH-

Question 9

Hypochlorite

Answer 9

ClO-

Question 10

Iodate

Answer 10

IO3 (charge = -1)

Question 11

Nitrate

Answer 11

NO3 (charge = -1)

Question 12

Nitrite

Answer 12

NO2 (charge = -1)

Question 13

Permanganate

Answer 13

MnO4 (charge = -1)

Question 14

Perchlorate

Answer 14

ClO4 (charge = -1)

Question 15

Thiocyanate

Answer 15

SCN-

Question 16

Carbonate

Answer 16

CO3 (charge = -2)

Question 17

Chromate

Answer 17

CrO4 (charge = -2)

Question 18

Dichromate

Answer 18

Cr2O7 (charge = -2)

Question 19

Oxalate

Answer 19

C2O4 (charge = -2)

Question 20

Peroxide

Answer 20

O2 (charge = -2)

Question 21

Sulfate

Answer 21

SO4 (charge = -2)

Question 22

Sulfite

Answer 22

SO3 (charge = -2)

Question 23

Phosphate

Answer 23

PO4 (charge = -3)

Question 24

Phosphite

Answer 24

PO3 (charge = -3)

Question 25

Arsenate

Answer 25

AsO4 (charge = -3)

Question 26

Ammonium

Answer 26

NH4 (charge = +1)