Question

There are three elements E, F and G with atomic number 19, 8 and 17 respectively. Give molecular formula of the compound formed between E and G .

Answer 1

The electronic configuration of $E$ is $2,8,8,1$ while that of $G$ is $2,8,7$.

Hence, $EG$ forms an ionic bond as $E$ looses one electron and gains octet configuration while $G$ accepts one electron and completes octet.
$E+G\to E^{+}{G}^{-}$

Therefore, the formula of compound formed between $E$ and $G$ is $EG$.