The difference between electronegativity and electron gain enthalpy is:

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 correct order of increasing ionic character in the molecules: LiF, K₂O, ${\mathrm{N}}_2, {\mathrm{SO}}_2$ and ClF₃ is:

1. ${\mathrm{N}}_2 < {\mathrm{ClF}}_3 < {\mathrm{SO}}_2< {\mathrm{K}}_2\mathrm{O} < \mathrm{LiF}$

2. ${\mathrm{N}}_2 < {\mathrm{ClF}}_3 < \mathrm{LiF} < {\mathrm{SO}}_2< {\mathrm{K}}_2\mathrm{O}$

3. ${\mathrm{SO}}_2< {\mathrm{K}}_2\mathrm{O} < {\mathrm{ClF}}_3 < \mathrm{LiF} < {\mathrm{N}}_2$

4. ${\mathrm{N}}_2 < {\mathrm{SO}}_2 < {\mathrm{ClF}}_3 < {\mathrm{K}}_2\mathrm{O} < \mathrm{LiF}$

CH₄ does not exhibit square planar geometry because:

 BeH₂ molecule has a zero dipole moment because -

The shapes of sp, ${\mathrm{sp}}^2$, ${\mathrm{sp}}^3$ orbitals formed due to hybridization of atomic orbitals would be respectively:

1. Trigonal planar, linear, tetrahedral

2. Linear, trigonal planar, tetrahedral

3. Linear, tetrahedral, trigonal planar

4. Tetrahedral, trigonal planar, linear

${\mathrm{BF}}_3+{\mathrm{NH}}_3\to {\mathrm{F}}_3\mathrm{B}.{\mathrm{NH}}_3$

The correct statement about the above reaction is :

The total number of sigma and pi bonds in C₂H₄ is:

1. 6 sigma bonds and 1 pi-bond.

2. 3 sigma bonds and 3 pi-bonds.

3. 5 sigma bonds and 1 pi-bond.

4. 2 sigma bonds and 2 pi-bonds.

The lone pairs of electrons can be defined as:

Be₂ molecule does not exist. The best explanation to explain this on the basis of the molecular orbital theory is:

1. The bond order of Be₂ is one.

2. The bond order of Be₂ is negative.

3. The bond order of Be₂ is zero.

4. The bond order of Be₂ is two.

The axial bonds are longer as compared to equatorial bonds in PCl₅ because: