The explanation for the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium would be :
| 1. | Pressure and volume |
| 2. | Lustre and brightness |
| 3. | Atomic size and effective nuclear charge |
| 4. | Availability in nature |
| Assertion (A): | Noble gases have the highest ionization enthalpies in their respective periods. |
| Reason (R): | Noble gases have stable closed-shell electronic configurations. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True and (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
| List-I | List-II | ||
| (A) | Al3+ < Mg2+ < Na+ < F– | (I) | Ionisation Enthalpy |
| (B) | B < C < O < N | (II) | Metallic character |
| (C) | B < Al < Mg < K | (III) | Electronegativity |
| (D) | Si < P < S < Cl | (IV) | Ionic radii |
| 1. | More shielding of paired electrons in 2p orbital of oxygen. |
| 2. | Half-filled stable configuration of nitrogen. |
| 3. | More Z effective of oxygen. |
| 4. | Small atomic size of oxygen. |
| 1. | The Electronegativity of elements increases when moving from left to right in the periodic table. |
| 2. | Ionisation enthalpy decreases in a group from top to bottom. |
| 3. | Non-metallic character increases in moving from left to right in a period. |
| 4. | Metallic character increases in moving from left to right in a period. |
Which one of the following elements, based on their electronic configurations, has the highest ionization enthalpy?
1.
2.
3.
4.
| 1. | \(\mathrm{I^- > I >I^+}\) (Radii) |
| 2. | \(\mathrm{I^- > I > I^+}\) (Ionisation energy) |
| 3. | \(\mathrm{Li^+}\) (aqueous) < \(\mathrm{Na^+}\) (aqueous) < \(\mathrm{K^+}\) (aqueous) (Radii) |
| 4. | \(\mathrm{F > Cl > Br > I}\) (Electron Affinity) |
For the second period elements the correct increasing order of first ionisation enthalpy is:
1. Li<Be<B<C<O<N<F<Ne
2. Li<Be<B<C<N<O<F<Ne
3. Li<B<Be<C<O<N<F<Ne
4. Li<B<Be<C<N<O<F<Ne