How does electron affinity vary down a group ?

How does electron affinity vary along a period ?

How does atomic radius vary down a group and along a period?

Name. the element, which has the highest electron gain enthalpy or electron affinity value in the periodic table.

Why noble gases have zero electron affinity values ?

How does ionisation energy vary along a period and down a group ?

How do the atomic radii vary in group and in period ? Give reasons for variation.

How does carbon gain four electrons?

Define electron gain enthalpy or electron affinity. How does it vary along the period and down the group ?

What is catenation ? How this property varies down the group ?