NCERT Class XII Chemistry
Chapter - The p-Block Elements
Questions with Solutions

The valence shell electronic configuration of group 15 elements isns2np3. Due to half-filled p-orbitals, these elements have extra stabilityassociated with them.
The common oxidation states of these elements are – 3, +3 and +5. Thetendency to exhibit –3 oxidation state decreases down the group. Thestability of +5 state decreases and that of +3 state increases down thegroup due to inert pair effect.
The size of group 15 elements increases down the group. There is aconsiderable increase in covalent radius from N to P. However, from Asto Bi only a small increase in covalent radius is observed. This is due topresence of completely filled d and or f orbitals in heavier members.
Down the group, ionisation enthalpy decreases due to increase in atomicsize. Due to stable half-filled configuration, they have much greater valuethan that of group 14 elements.
The electronegativity value, in general, decreases down the group withincreasing atomic size. However, amongst the heavier elements, thedifference is not that much pronounced.