Question

The correct order of atomic radii for the following species $S,P,Se$ and $Cl$ is:

• A.
  $Cl>S>Se>P$
• B.
  $Se>P>S>Cl$
• C.
  $S>Cl>Se>P$
• D.
  $Cl>S>P>Se$

Answer 1

The correct option is B

$Se>P>S>Cl$
Atomic radius is the distance from the centre of the nucleus to the outermost shell containing electrons. In other words, it is the distance from the center of the nucleus to the point up to which the density of the electron cloud is maximum.
The atomic radius decreases as we move from left to right across the period due to the increase in effective nuclear charge and increases down the group as a new energy shell is added to the atoms.
Hence, the correct order is B i.e,
$Se>P>S>Cl$