Give the relation between electronegativity, ionisation energy and electron affinity according to Mulliken.

Give a reason for the following.

Ionisation potential increases across a period, from left to right.

Write the scientific reason for metallic character goes on decreasing while going from left to right in a period.

Write the names from the description.

Two elements having valency $4$.

Write the scientific reason for the third period contains only eight elements even though the electron capacity of the third shell is $18$.

The elements of the second period of the periodic table are given below :

$\mathrm{Li}, \mathrm{Be}, \mathrm{B}, \mathrm{C}, \mathrm{N}, \mathrm{O}, \mathrm{F}$
(a) Give reasons to explain why atomic radius decreases from $\mathrm{Li}$ to $\mathrm{F}$.
(b) Identify the most (i) metallic and (ii) non-metallic element.

Write the names from the description.

The family of nonmetals having valency one.

Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with an explanation.

${}_7\mathrm{N},{ }_6\mathrm{C},{ }_8\mathrm{O},{ }_5\mathrm{B},{ }_{13}\mathrm{Al}$

Which is the most electronegative element among these?

Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with an explanation.

${}_6\mathrm{C}{,}_3\mathrm{Li}{,}_9\mathrm{F}{,}_7\mathrm{N}{,}_8\mathrm{O}$

Which of the above elements has the highest nonmetallic character?

The following table shows the position of six elements A, B, C, D, E and F in the periodic table:

Using the above table to answer the following questions :

Write the names from the description.

The group with valency zero.

Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with an explanation.

Which of the above elements has the highest metallic character?

Write the scientific reason for atomic radius goes on increasing down a group.