Question

The elements of the second period of the Periodic Table are given:$LiBeBCNOF$
Give reason to explain why atomic radii decreases from $Li$to$F$.

Answer 1

Reason to explain atomic radii decreases from$Li$ to $F$:

• On moving from$Li$ to$F$ in the second period, atomic number increases and subsequently, the nuclear charge also increases.
• This leads to a greater attractive pull of the electrons towards the nucleus, leading to the shrinkage of the atom although the number of electrons also increases.

Period II elements	$Li$	$Be$	$B$	$C$	$N$	$O$	$F$
Atomic radius	$152$	$111$	$88$	$77$	$74$	$66$	$64$

This is because, as each additional electron is placed within the same shell, thus all the electrons are equidistant from the nucleus.