The correct order among the following options is: 

1. F > N > C > Si > Ga - Non-metallic character.

2. F > Cl > O >N - Oxidising property.

3. C < Si > P > N  - Electron affinity value.

4. All of the above.

Which of the following statements is correct for an element that forms oxides in different oxidation states?

Assertion: The $5^{th}$ period of the periodic table contains 18 elements and not 32.

Reason: When n = 5, the value of l = 0, 1, 2, 3. The order in which the energy of available orbits 4d, 5s and 5p increases is 5s < 4d < 5p, and the total number of orbitals available is 9, thus 18 electrons can be accommodated.

Assertion : :The 4f- and 5f- inner transition series of elements are placed separately at
the bottom of the periodic table.

Reason : (i) This prevents the undue expansion of the periodic table i.e., maintains its structure.
(ii) This preserve the principle of classification by keeping elements with similar properties in a single column.

Assertion : Manganese (atomic number 25 ) has a less favourable electron affinity than its neighbours on either side because.

Reason : The Manganese has stable, ${\left[Ar\right]}^{18}3d^{5}4s^2$ electrons configuration.

Which of the following statements is not correct?

(1) The first ionization energies (in KJ $mo{l}^{-1}$) of carbon, silicon, germanium, tin, and lead are 1086, 786, 761, 708 and 715 respectively.

(2) Down the group, electronegativity decreases from B to Tl in boron family.

(3) Among oxides of the elements of carbon family, CO is neutral, GeO is acidic and SnO is amphoteric.

(4) The 4f- and 5f- inner transition elements are placed separately at the bottom of the periodic table to maintain its structure.

Which of the following statements are correct ?

1. (i), (iii) and (iv)                     
2. (ii), (iii) and (iv)
3. (i), (ii) and (iv)                         
4. (i), (ii) and (iii)  

The electron gain enthalpies of halogens in kJ mol^-1 are given below.

F =-332, Cl =-349, Br =-325, I =-295.

The lesser negative value for F as compared to that of Cl is due to:
 

1. Strong electron-electron repulsions in the compact 2p-subshell of F.

2. Weak electron-electron repulsions in the bigger 3p-subshell of Cl.

3. Smaller electronegativity value of F than Cl.

4. 1 & 2 both 

Which of the following orders are correct for the ionization energies?

(A) \(  B a   <   S r   <   C a        \)                  
(B) \(S^{2 -} < S   < S^{2 +}\)
(C) \(C   <   O < N\)
(D) \(M g   <   A l   <   S i\)

1. A, B and D                             
2. A, C and D
3. A, B and C                             
4. A, B, C and D