Q87P - Chemistry: Molecular Nature Of Matter And Change

Question

Give the name and formula of the compound formed from the following elements: (a) caesium and bromine; (b) sulphur and barium; (c) calcium and fluorine.

Step-by-Step Solution

Answer

(a) Name = Caesium bromide, Formula = CsBr

(b) Name = Barium sulphide, Formula = BaS

(c) Name = Calcium fluoride, Formula = ${\mathbf{CaF}}_{\mathbf{2}}$

Step 1: Compound of caesium and bromine

Caesium is electropositive having an oxidation state of +1 and gives ${\mathbf{Cs}}^{\mathbf{+}}$cation.

Bromine is electronegative having an oxidation state of -1 and gives ${\mathbf{Br}}^{\mathbf{-}}$ anion.

Thus, their oxidation states get exchanged and form caesium bromide having formula,CsBr.

Step 2: Compound of barium and sulphur

Barium is electropositive having an oxidation state of +2 and gives ${\mathbf{Ba}}^{\mathbf{2}\mathbf{+}}$cation.

Sulphur is electronegative having an oxidation state of -2 as ${\mathbf{S}}^{\mathbf{2}\mathbf{-}}$an anion.

Thus, their oxidation states get exchanged and form barium sulphide having formula BaS .

Step 3: Compound of calcium and fluorine

Calcium is electropositive having an oxidation state of +2 and gives ${\mathbf{Ca}}^{\mathbf{2}\mathbf{+}}$cation.

Fluorine is electronegative having an oxidation state of -1 as ${\mathbf{F}}^{\mathbf{-}}$an anion.

Thus, their oxidation states get exchanged and form a calcium fluoride having formula ${\mathbf{CaF}}_{\mathbf{2}}$.