Variable Valencies of Some Elements

Question 1

Iron

Answer 1

2 and 3 (ferrous and ferric)

Question 2

Copper

Answer 2

1 and 2 (cuprous and cupric)

Question 3

Mercury

Answer 3

1 and 2 (mercurous and mercuric)

Question 4

Lead

Answer 4

2 and 4 (plumbous and plumbic)

Question 5

Tin

Answer 5

2 and 4 (stannous and stannic)