- Which of the following pairs of elements would exhibit the greatest difference in atomic size?
a) Sodium and Magnesium
b) Fluorine and Chlorine
c) Potassium and Rubidium
d) Carbon and Silicon
Answer: d) Carbon and Silicon
Explanation: Carbon and silicon belong to the same group but different periods. Atomic size increases significantly as you move down a group due to the addition of electron shells.
- Which element has the highest ionization energy in Period 3?
a) Sodium (Na)
b) Magnesium (Mg)
c) Sulfur (S)
d) Argon (Ar)
Answer: d) Argon (Ar)
Explanation: Argon is a noble gas with a full valence shell, making it very stable and requiring a large amount of energy to remove an electron, hence the highest ionization energy in Period 3.
- Which of the following elements has the greatest tendency to form covalent bonds?
a) Oxygen (O)
b) Neon (Ne)
c) Sodium (Na)
d) Potassium (K)
Answer: a) Oxygen (O)
Explanation: Oxygen is highly electronegative and tends to share electrons to form covalent bonds. Neon, being a noble gas, does not form bonds easily, while sodium and potassium typically form ionic bonds.
- Which of the following is an amphoteric oxide?
a) Na₂O
b) MgO
c) Al₂O₃
d) SO₃
Answer: c) Al₂O₃
Explanation: Amphoteric oxides react with both acids and bases. Al₂O₃ is amphoteric, whereas Na₂O and MgO are basic oxides, and SO₃ is an acidic oxide.
- Which of the following has the highest electron affinity?
a) Oxygen (O)
b) Fluorine (F)
c) Chlorine (Cl)
d) Bromine (Br)
Answer: c) Chlorine (Cl)
Explanation: Chlorine has the highest electron affinity, even higher than fluorine, due to lower electron-electron repulsion in chlorine’s larger atomic size.
- Which of the following elements would have the lowest melting point?
a) Sodium (Na)
b) Magnesium (Mg)
c) Potassium (K)
d) Calcium (Ca)
Answer: c) Potassium (K)
Explanation: Among the alkali and alkaline earth metals listed, potassium has the largest atomic size and the weakest metallic bonding, leading to a lower melting point.
- Which of the following is true about ionization energy?
a) It decreases across a period
b) It increases down a group
c) It increases across a period
d) It remains constant across a period
Answer: c) It increases across a period
Explanation: Ionization energy increases across a period due to increasing nuclear charge, which makes it harder to remove an electron as you move from left to right.
- Which of the following elements has the lowest ionization energy?
a) Lithium (Li)
b) Sodium (Na)
c) Potassium (K)
d) Cesium (Cs)
Answer: d) Cesium (Cs)
Explanation: Cesium, being the farthest down in Group 1, has the largest atomic size and the weakest attraction between the nucleus and the outermost electron, leading to the lowest ionization energy.
- Which group in the periodic table has the highest ionization energies?
a) Alkali metals
b) Transition metals
c) Halogens
d) Noble gases
Answer: d) Noble gases
Explanation: Noble gases have very high ionization energies because they have a full valence shell and are very stable, making it difficult to remove an electron.
- Which of the following trends is true as you move down a group in the periodic table?
a) Electronegativity increases
b) Atomic radius decreases
c) Ionization energy decreases
d) Electron affinity increases
Answer: c) Ionization energy decreases
Explanation: Ionization energy decreases as you move down a group because the outermost electrons are farther from the nucleus, and the attraction is weaker.
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