Question

Write the formula of aluminium chloride ,Sodium oxide,hydrocloric acid, Calcium carbonate?​

Answer 1

Answer:

aluminum chloride = AlCl3

sodium oxygen = Na2O

calcium carbonate = CaCo3

Answer 2

Aluminium Chloride

Aluminium has 13 electrons and has 3 valence electrons (2+8+3=13)

Aluminium has valency of +3

Similarly Chlorine has valency of -1 (Valence electrons = 7)

Al   Cl

+3   -1

Thus the compound formed will have formula of

$Ag_1Cl_3$

or simply

$AgCl_3$

Sodium Oxide

Sodium has valency of +1

and oxygen has valency of -2

Na  O

+1   -2

Thus the compound formed will have formula of

$Na_2O$

Hydrochloric Acid

Hydrogen has valency of +1

( -1 as well w.r.t electronegativity, Higher standard concepts

Here chlorine is more electronegative so valency of Hydrogen is +1)

Chlorine has valency of -1

H   Cl

+1   -1

Thus the compound formed will have formula of

HCl

Calcium Carbonate

Calcium has valency of +2

and Carbonate $(CO_3)$ has valency of -2

Ca   CO3

+2     -2

Thus the compound formed will have formula of

$Ca(CO_3)\\or\\CaCO_3$