QUESTION 17

What is the formula of the compound formed between strontium ions and nitrogen ions?

A) SrN

B) Sr₂N₃

C) Sr₃N₂

D) SrN₂

QUESTION 18

The positive ion and the negative ion in MgSO₃ , respectively are:

	A.	Mg2+ & SO3 3-
	B.	Mg2+ & SO3 1-
	C.	Mg2+ & SO3 2-
	D.	Mg 3+ & SO3 3-

QUESTION 19

How many protons , Electrons and Neutrons are in Indium - 117 isotope ?

	A.	49 P ; 49 e ; 115 n
	B.	49 P ; 49 e ; 49 n
	C.	49 P ; 68 e ; 68 n
	D.	49 P ; 49 e ; 68 n
	E.	68 P ; 49 e ; 115 n

QUESTION 20

How many grams of chlorine are in 40.1 grams of pure Calcium chloride . You need to Write the correct chemical formulas for Calicum chloride, inorder to solve it?

Hint: Law of constant composition by mass

1 mole Ca = 40.1 g and 1 mole of Cl = 35.5 g Cl

		40.1 g Cl
		35.5 g Cl
		71.0 g Cl
		80.2 g Cl

QUESTION 21

Write the symbol for an isotope that contains 83 P ; 83 e and 128 n ?

		Bismuth - 212
		Bismuth - 210
		Bismuth - 209
		Bismuth - 211