Question

Which of the following correctly represents an ion pair and the ionic compound the ions form

Answer 1

Answer:

It's a.

Explanation:

That would be Ca2+ , F- . We see in the compound CaF2 the  signs balance to give a neutral compound, 2+ balances with 2-.

Answer 2

Answer:  a. $Ca^{2+}$, $F^-$, $CaF_2$

Explanation:

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

(a) calcium and fluorine: Here calcium is having an oxidation state of +2 called as $Ca^{2+}$ cation and fluorine $F^{-}$ is an anion with oxidation state of -1. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral $CaF_2$. called as calcium fluoride.

(b) sodium and chlorine: Here sodium is having an oxidation state of +1 called as $Na^{+}$ cation and chlorine $Cl^{-}$ is an anion with oxidation state of -1. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral $NaCl$ called as sodium chloride.

(c) barium and oxygen : Here barium is having an oxidation state of +2 called as $Ba^{2+}$ cation and oxygen $O^{2-}$ is an anion with oxidation state of -2. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral $BaO$ called as barium oxide.

(d) lead and oxygen : Here lead is having an oxidation state of +4 called as $Pb^{4+}$ cation and oxygen $O^{2-}$ is an anion with oxidation state of -2. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral $PbO_2$ called as lead(IV) oxide.