NCERT Solutions for Chapter: Classification of Elements and Periodicity in Properties, Exercise 1: Short Answer Type

Arrange the elements $\mathrm{N}, \mathrm{P}, \mathrm{O} \mathrm{and} \mathrm{S}$ in the order of increasing first ionisation enthalpy. Give the reason for the arrangement assigned. 

Arrange the elements $\mathrm{N}, \mathrm{P}, \mathrm{O} \mathrm{and} \mathrm{S}$ in the order of increasing non-metallic character. Give the reason for the arrangement assigned. 

Explain the deviation In Ionisation enthalpy of some elements from the general trend by using Figure

Explain the following:
Electronegativity of elements increases on moving from left to right in the periodic table. 

Explain the following:

Ionisation enthalpy decrease in a group from top to bottom?

How does the metallic and non-metallic character vary on moving from left to right in a period?

The radius of ${\mathrm{Na}}^{+}$ cation is less than that of $\mathrm{Na}$ atom. Give reason.

Among alkali metals which element do you expect to be least electronegative and why?