Q. No.The ionic radius indicates the distance between the nucleus and:
1. Outermost shell of an atom.
2. Outermost shell of an ion.
3. Outermost shell of the cation only.
4. Outermost shell of the anion only.
The trend of atomic radius in a period and a group is :
| 1. | Generally decreases from right to left across a period and increases down a group. |
| 2. | Generally increases from left to right across a period and decreases down a group. |
| 3. | Generally decreases from left to right across a period and increases down a group. |
| 4. | Generally remains same from left to right across a period and increases down a group. |
Anions generally possess larger atomic radii than their corresponding neutral atoms. This is primarily due to:
| 1. | An anion has a fewer number of electrons than its parent atom |
| 2. | An anion has the same number of electrons as its parent atom. |
| 3. | An anion has a higher effective nuclear charge. |
| 4. | An anion has more electrons than its parent atom |
The energy of an electron in the ground state of the hydrogen atom is . The ionization enthalpy of atomic hydrogen in terms of J is:
1. 2.81 × 106 J mol
2. 1.31 × 106 J mol
3. 2.31 × 106 J mol
4. 1.81 × 106 J mol
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 |
The ionization enthalpy of the main group elements tends to decrease down a group due to,
1) Increase in the atomic size of elements and increase in the shielding effect
2) Decrease in the atomic size of elements and increase in the shielding effect
3) Increase in the atomic size of elements and decrease in the shielding effect
4) Decrease in the atomic size of elements and decrease in the shielding effect
The first ionization enthalpy values (in kJ mol–1) of group 13 elements are :
| B | Al | Ga | In | Tl |
| 801 | 577 | 579 | 558 | 589 |
The explanation for the deviation from the general trend can be:
1. B has filled subshells, giving it unusually high ionization energy
2. Ga has a filled 3d¹⁰ subshell, increasing the effective nuclear charge
3. Indium has a very small atomic size, lowering its ionization energy
4. Tl has an unusually low nuclear charge, decreasing ionization energy
Which of the following pairs correctly identifies the element with the more negative electron gain enthalpy in each set?
(i) O or F (ii) F or Cl
1. O, Cl
2. F, F
3. O, F
4. F, Cl
The relationship between 1st and 2nd electron gain enthalpy of oxygen atom (O) would be :
| 1. | Both values of electron gain enthalpy are negative |
| 2. | The 1st electron gain enthalpy of (O) is negative while 2nd is positive |
| 3. | Both values of electron gain enthalpies are positive |
| 4. | The 1st electron gain enthalpy of (O) is positive while 2nd is negative |
The basic difference between the electron gain enthalpy (Ea) and electronegativity (EN) is:
| 1. | Ea is the tendency to lose electrons, while EN is the tendency to repel the shared pairs of electrons. |
| 2. | Ea is the tendency to gain neutrons, while EN is the tendency to attract the shared pairs of electrons. |
| 3. | Ea is the tendency to donate electrons, while EN is the tendency to attract the shared pairs of molecules. |
| 4. | Ea is the tendency to gain electrons, while EN is the tendency to attract the shared pairs of electrons. |
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