Classification ...

Which one of the following is not a monoatomic element ? 

Refer to change in the properties of elements on moving from left to right across a period of the Periodic Table. For each property, choose the correct answer.
The electron affinity of the elements in groups 1 to 7:

Increasing order of electron gain enthalpy is: 

Electronegativity of chlorine is three. Electron affinity of chlorine is 3.6ev/ atom. The ionisation potential of chlorine is what ev/ atom?

An element having electronic configuration $$1s^{2}, 2s^{2}, 2p^{6}, 3s^{2},3p^{6}, 4s^{1}$$ will form:

Match the items of Columns I and II and mark the correct option

Which of the following is the correct order for electron gain enthalpy? 

Which of the following species has the highest electron gain enthalpy? 

Consider the following conversions :
That according to given information the incorrect statement is :

Second electron gain enthalpy :