Question

Given below are two statements:
Statement (I): The first ionisation enthalpy of group 14 elements is higher than the corresponding elements of group 13.
Statement (II): Melting points and boiling points of group 13 elements are in general much higher than those of the corresponding elements of group 14. Choose the most appropriate answer from the options given below:

• A. Statement I is correct but Statement II is incorrect
• B. Statement I is incorrect but Statement II is correct
• C. Both Statement I and Statement II are incorrect
• D. Both Statement I and Statement II are correct

Hint:

Ionisation enthalpy increases across a period as the nuclear charge increases, but the melting and boiling points of the elements generally follow the trends in atomic size and bonding strength.

Answer 1

The Correct Option is A

This analysis evaluates two statements regarding Group 13 and Group 14 elements. We will assess each statement independently.

1. Statement I: Group 14 elements exhibit higher first ionization enthalpies than their corresponding Group 13 counterparts.
   • Ionization enthalpy is the energy required to remove an electron from an atom's outermost shell in the gaseous state. Factors influencing it include atomic size, nuclear charge, and electron configuration.
   • In the same period, Group 14 elements possess more protons and a higher effective nuclear charge than Group 13 elements. This results in a stronger attraction to their valence electrons and, consequently, a higher ionization enthalpy.
   • Therefore, Statement I is accurate: the first ionization enthalpy of Group 14 elements is indeed greater than that of Group 13 elements. Statement I is correct.
2. Statement II: Group 13 elements generally have significantly higher melting and boiling points than the corresponding Group 14 elements.
   • Melting and boiling points are dictated by the bonding types and structural arrangements of elements.
   • Group 14 elements typically form covalent network structures, which generally yield higher melting and boiling points (e.g., Carbon in diamond, Silicon) compared to the metallic bonding prevalent in Group 13 elements.
   • For instance, carbon in its diamond allotrope possesses exceptionally high melting point, far exceeding those of boron or aluminum.
   • Consequently, the general trend indicates that melting and boiling points of Group 14 elements are higher than those of Group 13 elements. Statement II is incorrect.

Based on this examination, we conclude: Statement I is correct, while Statement II is incorrect. The correct option is:

Statement I is correct but Statement II is incorrect