Question

Write the names and symbols of the constituent elements and identify their valencies from the molecular formulae given below.

KCl, HBr, MgBr₂, K₂O, NaH, CaCl_2, CCl_4, HI, H₂S, Na₂S, FeS, BaCl₂

Answer 1

Compounds	Name of compounds	Symbol of constituent elements	Valency of constituent elements
KCl	Potassium chloride	K, Cl	K = 1, Cl = 1
HBr	Hydrogen bromide	H, Br	H = 1, Br = 1
MgBr2	Magnesium bromide	Mg, Br	Mg = 2, Br = 1
K2O	Potassium oxide	K, O	K = 1, O = 2
NaH	Sodium hydride	Na, H	Na = 1, H = 1
CaCl2	Calcium chloride	Ca, Cl	Ca = 2, Cl = 1
CCl4	Carbon tetrachloride	C, Cl	C = 4, Cl = 1
HI	Hydrogen iodide	H, I	H = 1, I = 1
H2S	Hydrogen sulphide	H, S	H = 1, S = 2
Na2S	Sodium sulphide	Na, S	Na = 1, S = 2
FeS	Iron (II) Sulfide	Fe, S	F = 2, S = 2
BaCl2	Barium chloride	Ba, Cl	Ba = 2, Cl = 1