What is the difference between electronegativity and electron gain enthalpy?

1.	An element has a constant value of the electron gain enthalpy but not of electronegativity.
2.	There is no difference between these two terms.
3.	An element has a constant value of electronegativity but not of electron gain enthalpy.
4.	None of the above.

The ionic radii vary in :

Choose the correct option :

1. (a), (c)

2. (b), (c)

3. (c), (d)

4. (b), (d)

Match the following isoelectronic species in Column-I and Column-II: 

The correct order of ionization energy of W, X, Y and Z is-

Consider the following curves:

X represents group with highest atomic radius. The element that belongs to Y group can be : 

In the following graph of variation of ionization energy with atomic number, X, Y, and Z represent elements.

The group number of X, Y, and Z elements is:

The graph between ionization energy and atomic number for the first group elements is shown below:

The element represented by Y in the graph above is:

1. Cs 

2. Rb

3. Ca

4.  K

Abnormally high ionization enthalpy of B as depicted in the graph below can be due to : 

1. Completely filled 2p subshell.

2. Completely filled 2s subshell.

3. Completely filled 3d subshell.

4. Completely filled 4f subshell.

The correct graph depicting ionization energies for 2^nd period elements is:

1.
2.
3.
4.	None of the above

The incorrect statement about ionization enthalpy is: