First Chapter Solved Exercise MCQs Of FSC Second Year Chemistry
written by Almas AnwarThe First Chapter Solved Exercise MCQs of FSC 2nd-year Chemistry provides a complete set of solved multiple-choice questions (MCQs). Each MCQ comes with a brief explanation to help you understand the correct answer. These solutions are designed to support students in preparing for their exams, making complex concepts easier to grasp and ensuring a solid foundation for success.
First chapter solved MCQs with explanation
1. Keeping in view the size of atoms, which order is the correct one?
(a) Mg > Sr
(b) Ba > Mg
(c) Lu > Ce
(d) Cl > I
Explanation: Option (b) is correct. Atomic size increases down a group due to more electron shells. Ba is below Mg in Group 2, so Ba is larger.
Other options:
(a) Mg < Sr: Sr is below Mg in Group 2, so Sr is larger.
(c) Lu < Ce: Lu is smaller than Ce due to more protons pulling electrons closer.
(d) Cl < I: I is larger than Cl as it’s lower in Group 17.
2. Mark the correct statement:
(a) Na⁺ is smaller than Na atom
(b) Na⁺ is larger than Na atom
(c) Cl⁻ is smaller than Cl atom
(d) Cl⁻ and Cl atom are equal in size
Explanation: Option (a) is correct. Because When a sodium atom (Na) loses one electron to form Na⁺, the number of electrons decreases, reducing electron-electron repulsion. As a result, the remaining electrons are pulled closer to the nucleus, making Na⁺ smaller than the neutral Na atom.
3. Mark the correct statement:
(a) All lanthanides are present in the same group
(b) All halogens are present in the same period
(c) All alkali metals are present in the same group
(d) All noble gases are present in the same period
Explanation: Option (c) is correct. Alkali metals (like lithium, sodium, potassium, etc.) are all found in Group 1 of the periodic table.
The other statements are incorrect:
- Noble gases are in the same group (Group 18) but not the same period.
- Lanthanides are in the same period but not the same group.
- Halogens are in the same group (Group 17) but not the same period.
4. Which statement is incorrect?
(a) All metals are good conductors of electricity.
(b) All metals are good conductors of heat.
(c) All metals form positive ions.
(d) All metals form acidic oxides.
Explanation: Option (d) is correct. Metals typically form basic oxides or amphoteric oxides (which can behave as both acidic and basic), but not acidic oxides. Acidic oxides are generally formed by non-metals. For example, sodium forms sodium oxide (Na₂O), which is a basic oxide.
5. Which statement is correct?
(a) Hydrogen resembles in properties with IA, IVA, and VIIA elements.
(b) Hydrogen resembles in properties with IIIA, IVA, and VA elements.
(c) Hydrogen resembles in properties with IIA, IVA, and VIA elements.
(d) Hydrogen resembles in properties with IIA, IIIA, and VIIA elements.
Explanation: Option (a) is correct. Hydrogen shows similarities with these three groups in different aspects of bonding and electron configuration:
- IA (Group 1): Hydrogen has one electron like alkali metals and can lose this electron to form a positive ion (H⁺).
- IVA (Group 14): Hydrogen can also share electrons like carbon and form covalent bonds.
- VIIA (Group 17): Hydrogen resembles halogens because it can gain one electron to form a negative ion (H⁻).
6. Mark the correct statement:
(a) The ionization energy of calcium is lower than that of barium.
(b) The ionization energy of calcium is lower than that of magnesium.
(c) The ionization energy of calcium is higher than that of beryllium.
(d) The ionization energy of calcium is lower than that of strontium.
Explanation: Option (b) is correct. Ionization energy generally decreases down a group because the outer electrons are farther from the nucleus and experience more shielding. Calcium is below magnesium in Group 2, so it has a lower ionization energy compared to magnesium.
7. Mark the correct statement:
(a) Electron affinity is a measure of energy required to remove the electron.
(b) Electron affinity is a measure of energy released by adding an electron.
(c) Electron affinity is a measure of energy required to excite an electron.
(d) Electron affinity is a measure of energy released by removing an electron.
Explanation: Option (b) is correct. Electron affinity refers to the amount of energy released when an electron is added to a neutral atom, turning it into a negatively charged ion. This energy release happens because the atom becomes more stable after gaining an electron.
8. Mark the correct statement:
(a) Metallic character increases down the group.
(b) Metallic character increases from left to right along a period.
(c) Metallic character remains the same from left to right along a period.
(d) Metallic character remains the same down the group.
Explanation: Option (a) is correct. Atomic size increases down a group, making it easier for atoms to lose electrons, which increases their metallic character. From left to right along a period, atomic size decreases, so metallic character decreases.
9. Mark the correct statement:
(a) Melting points of halogens decrease down the group.
(b) Melting points of halogens increase down the group.
(c) Melting points of halogens remain the same throughout the group.
(d) Melting points of halogens first increase and then decrease down the group.
Explanation: Option (b) is correct. As you move down Group 17, the size and mass of halogen atoms increase, leading to stronger van der Waals forces between molecules, resulting in an increase in melting points.
10. Mark the correct statement:
(a) Covalent character of metal halides increases from left to right in a period.
(b) Boiling points of Group IVA hydrides decrease down the group.
(c) Ionic character of hydrides increases from left to right in a period.
(d) The basicity of Group IIA oxides decreases on descending the group.
Explanation: Option (d) is correct.
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