Question

In how many shells do the valence electrons of iodine lie?

Answer 1

Hint: From the electronic configuration of Iodine, we can know about the valence electrons present and thereby finding the number of shells in which valence electrons of iodine lie.

Complete step by step answer: Iodine, I, is located in period 5 and group 17 of the periodic table.
The Atomic Number of element Iodine is $53$.
The Atomic Mass of Iodine is $126.90u$.
The Electronic Configuration of the Iodine is $$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^5$$ or we can write it as $$\left[Kr\right]4d105s25p5$$.
Iodine has 7 valence electrons in the valence shell which means that there are 7 electrons in its outer shell.
A neutral iodine atom will have a total of 53 electrons around its nucleus. Out of these 53 electrons, some are known as valence electrons while others are known as core electrons.

$n_{total}=n_{core}+n_{valence}$

Valence Electrons are the electrons located on the highest energy level of the atom.
In the case of Iodine, the highest energy level is $n=5$. So, after adding the electrons present in subshell $5s,5p$ total number of valence electrons come out to be seven. And core electrons are $53-7=46$.

As, we have discussed above, valence electrons are present in subshell $5sand5p$.

Therefore, the number of shells in which valence electrons of iodine lies is 5.

Note: Additional Information: Uses of Iodine: Iodine has a large number of uses. Iodide salts are used in disinfectants, printing inks, animal feed supplements and photographic chemicals. It is also used as dyes and catalysts. For making polarizing filters for LCD displays, Iodine is used.