Question

In group $17$ how many valence electrons does Iodine have?

Answer 1

Valence Electrons:

1. The electron present in the outermost shell of an atom is called the valence electron.
2. These valance electrons are responsible for participating in chemical reactions.
3. They participate in chemical reactions by forming chemical bonds with atoms of other elements or the same element.

Valance Electrons in Iodine:

1. Group $17$ is of halogens or non-metals.
2. Iodine contains $7$ electrons in its outer shell.
3. They need to gain $1$ more to complete an octet.
4. Therefore, the electronic configuration can be given as $\left(\mathrm{Kr}\right)4{\mathrm{d}}^{10}5{\mathrm{s}}^{2}5{\mathrm{p}}^5$.
5. Hence, in the last subshell, there are $7$ valence electrons and valency is $1$.

Hence, there are $7$ valence electrons in Iodine $\left(\mathrm{I}\right)$.