With which of the following electronic configuration an atom has the lowest ionisation enthalpy?
With which of the following electronic configuration an atom has the lowest ionisation enthalpy?
$1 s^2 2 s^2 2 p^3$
$1 s^2 2 s^2 2 p^6 3 s^1$
$1 s^2 2 s^2 2 p^6$
$1 s^2 2 s^2 2 p^5$
Solution
The factors on which the ionisation energy depend is atomic size. I.E. decreases as the atomic size increases. So the attractive force decreases.
Also as the number of shells increases screening effect also increases and hence the I.E. tends to decrease.
Related Theory
The more electron shells there are, the greater the shielding effect experienced by the outermost electrons. As a result, atoms will be larger.