- Which of the following is a noble gas?
a) Hydrogen (H)
b) Oxygen (O)
c) Neon (Ne)
d) Nitrogen (N)
Answer: c) Neon (Ne)
Explanation: Neon is a noble gas, which is characterized by a full outer electron shell, making it chemically inert under most conditions.
- Which of the following elements shows the greatest tendency to form cations?
a) Fluorine (F)
b) Potassium (K)
c) Oxygen (O)
d) Nitrogen (N)
Answer: b) Potassium (K)
Explanation: Potassium is an alkali metal, which readily loses an electron to form a K⁺ cation. Fluorine and oxygen tend to form anions, and nitrogen typically forms anions or covalent bonds.
- Which of the following oxides is acidic?
a) Na₂O
b) MgO
c) SO₂
d) CaO
Answer: c) SO₂
Explanation: SO₂ is a non-metal oxide, which reacts with water to form sulfurous acid, making it an acidic oxide. Na₂O, MgO, and CaO are basic oxides.
- Which of the following elements has the smallest ionic radius?
a) Cl⁻
b) F⁻
c) K⁺
d) Na⁺
Answer: d) Na⁺
Explanation: Na⁺ has a smaller ionic radius compared to K⁺, Cl⁻, and F⁻ due to its smaller size and higher effective nuclear charge, which pulls the electrons closer to the nucleus.
- Which of the following is a d-block element?
a) Sodium (Na)
b) Chlorine (Cl)
c) Iron (Fe)
d) Phosphorus (P)
Answer: c) Iron (Fe)
Explanation: Iron (Fe) is a transition metal located in the d-block of the periodic table. Sodium, chlorine, and phosphorus are s- and p-block elements.
- Which of the following elements has the most positive electron affinity?
a) Neon (Ne)
b) Nitrogen (N)
c) Phosphorus (P)
d) Sulfur (S)
Answer: a) Neon (Ne)
Explanation: Neon, a noble gas, has a positive electron affinity because it is energetically unfavorable to add an electron to its full outer shell.
- Which of the following has the highest ionization energy?
a) Lithium (Li)
b) Beryllium (Be)
c) Boron (B)
d) Carbon (C)
Answer: d) Carbon (C)
Explanation: Ionization energy increases across a period. Carbon, being the farthest right of the elements listed, has the highest ionization energy.
- Which of the following has the largest atomic radius?
a) Sodium (Na)
b) Magnesium (Mg)
c) Aluminum (Al)
d) Silicon (Si)
Answer: a) Sodium (Na)
Explanation: Atomic radius decreases across a period from left to right. Sodium, being the first element in Period 3, has the largest atomic radius among the elements listed.
- Which of the following oxides is amphoteric?
a) Na₂O
b) MgO
c) Al₂O₃
d) SO₃
Answer: c) Al₂O₃
Explanation: Al₂O₃ is an amphoteric oxide, meaning it can react with both acids and bases. Na₂O and MgO are basic oxides, while SO₃ is an acidic oxide.
- Which of the following elements is most likely to form a covalent bond?
a) Potassium (K)
b) Magnesium (Mg)
c) Chlorine (Cl)
d) Sodium (Na)
Answer: c) Chlorine (Cl)
Explanation: Chlorine, a non-metal with high electronegativity, tends to share electrons to form covalent bonds, unlike potassium and sodium, which form ionic bonds.
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