If the first ionisation enthalpy of Li, Be and C respectively are 520, 899, 1086 kJ/mol, the first ionisation enthalpy (in kJ/mol) of B will be
1
487
2
950
3
801
4
1402
Official Solution
Correct Option: (3)
Step 1: Ionisation enthalpy generally increases across a period from left to right. From the given values, we observe that the ionisation enthalpy of Li is 520 kJ/mol, Be is 899 kJ/mol, and C is 1086 kJ/mol.
Step 2: The ionisation enthalpy of B, being between Be and C, will likely be between 899 and 1086 kJ/mol. The most reasonable estimate for B's ionisation enthalpy is 801 kJ/mol.
Step 3: This follows the trend of increasing ionisation enthalpy across the period. Thus, the correct value of the first ionisation enthalpy of B is closest to 801 kJ/mol.
02
PYQ 2024
medium
chemistryID: ap-eamce
Match the following:
1
A-II, B-IV, C-I, D-III
2
A-IV, B-II, C-I, D-III
3
A-III, B-IV, C-IV, D-I
4
A-III, B-III, C-IV, D-I
Official Solution
Correct Option: (1)
Electron gain enthalpy is the energy change when an electron is added to an atom in the gaseous state.
- Fluorine (F) has an electron gain enthalpy of kJ/mol (II).
- Chlorine (Cl) has an electron gain enthalpy of kJ/mol (IV).
- Oxygen (O) has an electron gain enthalpy of kJ/mol (I).
- Sulfur (S) has an electron gain enthalpy of kJ/mol (III). Thus, the correct matching is:
03
PYQ 2024
medium
chemistryID: ap-eamce
Which of the following sets of elements is not correctly arranged according to the given property?
1
(Electron gain enthalpy)
2
(Electronegativity)
3
(Metallic radius)
4
(Metallic nature)
Official Solution
Correct Option: (4)
Step 1: Understanding Periodic Trends 1. Electron Gain Enthalpy: The correct trend follows , as oxygen has a lower electron gain enthalpy due to its small size and electron repulsion. 2. Electronegativity: Fluorine has the highest electronegativity, followed by oxygen and chlorine, making a correct order. 3. Metallic Radius: Across a period, metallic radius decreases, while down a group, it increases. The given order is incorrect since aluminum is a metalloid and has a much smaller atomic radius than sodium and lithium. 4. Metallic Nature: Metallic nature increases down the group. The correct order should be , not . Thus, the incorrect arrangement is option (4) .
04
PYQ 2024
medium
chemistryID: ap-eamce
Match the following:
1
A-III, B-IV, C-I, D-II
2
A-IV, B-III, C-I, D-II
3
A-III, B-I, C-IV, D-II
4
A-II, B-IV, C-I, D-III
Official Solution
Correct Option: (3)
Step 1: Identify Group Numbers of Elements Moscovium (Mc) belongs to group 15. Livermorium (Lv) belongs to group 16. Flerovium (Fl) belongs to group 14. Tennessine (Ts) belongs to group 17. Thus, the correct match is:
