Question

The element with highest electronegativity among the following is:

• A. C
• B. Si
• C. Ge
• D. Sn

Answer 1

The correct option is A C

In group 14, carbon is the most electronegative element. On moving down the group, the electronegativity decreases due to increase in size and weaker nuclear charge. In group 14, electronegativity decreases from C to Pb in an irregular manner. The electronegativity value for elements from Si to Pb are almost the same. This is due to the poor shielding effects of intervening d and f-orbitals.

THEORY
Electronegativity:
As we know, across the period the electrons get added up to the same shell. This will increase the effective nuclear charge between the nucleus and outermost electron. Thus, nuclear charge attracts the bond pair of electrons toward itself. Thus, across the period electronegativity increased. Therefore,
Electronegativity of Elements of group 13 is lower than Electronegativity of Elements of group 14.
The electronegativity value for elements from Si to Pb are almost the same.
Ionization enthalpy:
In general, the ionization enthalpy decreases down the group because for each successive member one extra shell of electrons is added. This reduces the attraction between the nucleus and the outermost electron. Therefore, it is easy to remove the electron from the outermost shell.
1st ionisation enthalpy of group 14 is greater than 1st ionisation enthalpy of group 13 because across the period, the electrons get added up to the same shell. This will increase the effective nuclear charge between the nucleus and outermost electron. So, it needs higher energy to remove the outer electron. Hence, 1st ionisation enthalpy of group 14 is greater than 1st ionisation enthalpy of group 13.
Small decreases in ${\Delta }_i{H}_1$ from Si to Ge to Sn and slight increase in ${\Delta }_i{H}_1$ from Sn to Pb.
Consequence of poor shielding effects of intervening d and f-orbitals and increase in size of the atom.