# Question #1b7a2

##### 1 Answer

(a) The given formula is AlCl . It is incorrect. The correct formula can be written if we know the valencies of different elements. The valency of Aluminum is +3 as it loses three electrons to achieve stable noble gas configuration like Neon.

Each Chlorine atom has valency of -1 as it gains one electron to achieve stable noble gas configuration like Argon.

for one Aluminum atom ,three chlorine atoms can unite as to make +3 charge equal to -3 charge.

So the formula will be

S

So the formula will be

BaOH2 ( incorrect). The valency of Barium is +2 as it loses two electrons to achieve stable noble gas configuration.

Each Hydroxide Ion

To balance the positive and negative charges

for one barium ion ,two hydroxide ions can unite as to make +2 charge equal to -2 charge.

The formula is

FeO