- Which of the following elements has the greatest ability to form multiple oxidation states?
a) Sodium (Na)
b) Potassium (K)
c) Iron (Fe)
d) Aluminum (Al)
Answer: c) Iron (Fe)
Explanation: Iron, a transition metal, can form multiple oxidation states (e.g., +2, +3), whereas sodium, potassium, and aluminum typically form only one oxidation state.
- Which of the following elements is most likely to exhibit allotropy?
a) Carbon (C)
b) Sodium (Na)
c) Magnesium (Mg)
d) Chlorine (Cl)
Answer: a) Carbon (C)
Explanation: Carbon exhibits allotropy, meaning it exists in different structural forms like diamond, graphite, and fullerenes. The other elements listed do not exhibit this property.
- Which of the following elements has the lowest electronegativity?
a) Fluorine (F)
b) Oxygen (O)
c) Sodium (Na)
d) Sulfur (S)
Answer: c) Sodium (Na)
Explanation: Sodium, being an alkali metal, has a very low electronegativity compared to the non-metals listed, which are more electronegative.
- Which of the following has the smallest ionic radius?
a) Na⁺
b) K⁺
c) Mg²⁺
d) Cl⁻
Answer: c) Mg²⁺
Explanation: Mg²⁺ has a smaller ionic radius compared to Na⁺, K⁺, and Cl⁻ because it has lost two electrons, leading to a higher effective nuclear charge that pulls the remaining electrons closer to the nucleus.
- Which of the following oxides is amphoteric?
a) Na₂O
b) MgO
c) ZnO
d) SO₂
Answer: c) ZnO
Explanation: ZnO is amphoteric, meaning it can react with both acids and bases. Na₂O and MgO are basic oxides, while SO₂ is an acidic oxide.
- Which of the following halogens has the lowest electronegativity?
a) Fluorine (F)
b) Chlorine (Cl)
c) Bromine (Br)
d) Iodine (I)
Answer: d) Iodine (I)
Explanation: Electronegativity decreases down the group in halogens. Iodine, being the farthest down the group, has the lowest electronegativity.
- Which of the following elements has the highest electron affinity?
a) Nitrogen (N)
b) Oxygen (O)
c) Chlorine (Cl)
d) Fluorine (F)
Answer: c) Chlorine (Cl)
Explanation: Chlorine has a higher electron affinity than fluorine due to reduced electron-electron repulsion in its larger atomic size. Oxygen and nitrogen have lower electron affinities.
- Which of the following is an alkali metal?
a) Calcium (Ca)
b) Magnesium (Mg)
c) Potassium (K)
d) Iron (Fe)
Answer: c) Potassium (K)
Explanation: Potassium is an alkali metal located in Group 1 of the periodic table, characterized by its high reactivity and tendency to form +1 ions.
- Which of the following has the highest first ionization energy?
a) Boron (B)
b) Carbon (C)
c) Nitrogen (N)
d) Oxygen (O)
Answer: c) Nitrogen (N)
Explanation: Nitrogen has a half-filled p-orbital, which makes it more stable and requires more energy to remove an electron, resulting in a higher first ionization energy than boron, carbon, and oxygen.
- Which of the following elements is a p-block element?
a) Sodium (Na)
b) Iron (Fe)
c) Nitrogen (N)
d) Calcium (Ca)
Answer: c) Nitrogen (N)
Explanation: Nitrogen is a p-block element found in Group 15. Sodium, iron, and calcium belong to the s- and d-blocks, respectively
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