Question

$\left(\mathrm{a}\right)$ The electropositive nature of the element(s) increases down the group and decreases across the period

$\left(\mathrm{b}\right)$Electronegativity of the element decreases down the group and increases across the period

$\left(\mathrm{c}\right)$ Atomic size increases down the group and decreases across a period (left to right)

$\left(\mathrm{d}\right)$ Metallic character increases down the group and decreases across a period.

Based on the above trends of the periodic table, answer the following about the elements with atomic numbers $3$ to $9$. Name the element with the smallest atomic size.

Answer 1

Atomic size:

1. The distance between an atom's nucleus and its outermost shell is measured in atomic size.
2. As we progress from one period to the next, the atomic size of a group grows due to the insertion of shells.
3. The atomic size reduces from left to right in a period as the number of shells remains constant but the nuclear charge rises.
4. As a result, electrons from the outermost shell are drawn towards the nucleus, shrinking the size of the nucleus.
5. The element with an atomic number $9$ i.e. Fluorine has the smallest size as the number of electrons is higher in its shell due to which the attraction between electron and nucleus rises and size reduces.

Therefore, the element with atomic number $9$ i.e. Fluorine has the smallest size.