- Which of the following has the largest atomic radius?
a) Boron (B)
b) Oxygen (O)
c) Nitrogen (N)
d) Fluorine (F)
Answer: a) Boron (B)
Explanation: Atomic radius decreases across a period from left to right. Boron is the farthest left in the periodic table compared to oxygen, nitrogen, and fluorine, and thus has the largest atomic radius.
- Which of the following elements has the smallest atomic radius?
a) Lithium (Li)
b) Sodium (Na)
c) Potassium (K)
d) Cesium (Cs)
Answer: a) Lithium (Li)
Explanation: Atomic radius increases as you move down a group. Lithium, being the first element in Group 1, has the smallest atomic radius compared to the other alkali metals.
- The first ionization energy is highest for which of the following elements?
a) Helium (He)
b) Neon (Ne)
c) Argon (Ar)
d) Krypton (Kr)
Answer: a) Helium (He)
Explanation: Helium has the highest first ionization energy of all elements because its electrons are closest to the nucleus and are held tightly by the nuclear charge.
- Which of the following elements has the most negative electron affinity?
a) Fluorine (F)
b) Chlorine (Cl)
c) Bromine (Br)
d) Iodine (I)
Answer: b) Chlorine (Cl)
Explanation: Chlorine has a more negative electron affinity than fluorine due to less electron-electron repulsion in its larger size, making it easier to accept an electron.
- Which of the following oxides is the most basic?
a) MgO
b) Al₂O₃
c) SiO₂
d) P₂O₅
Answer: a) MgO
Explanation: MgO is a basic oxide that reacts with water to form a basic solution (magnesium hydroxide). Al₂O₃ is amphoteric, and SiO₂ and P₂O₅ are acidic oxides.
- Which of the following elements would have the highest electronegativity?
a) Nitrogen (N)
b) Phosphorus (P)
c) Arsenic (As)
d) Antimony (Sb)
Answer: a) Nitrogen (N)
Explanation: Electronegativity decreases down a group. Nitrogen, being at the top of Group 15, has the highest electronegativity compared to the other elements listed.
- The most metallic element among the following is:
a) Sodium (Na)
b) Magnesium (Mg)
c) Aluminum (Al)
d) Silicon (Si)
Answer: a) Sodium (Na)
Explanation: Metallic character decreases across a period from left to right. Sodium, being the farthest left among the elements listed, has the highest metallic character.
- Which of the following elements has the highest second ionization energy?
a) Sodium (Na)
b) Magnesium (Mg)
c) Potassium (K)
d) Calcium (Ca)
Answer: a) Sodium (Na)
Explanation: After sodium loses one electron, it achieves a stable noble gas configuration (Ne). The second ionization energy is extremely high because removing another electron would disturb this stable configuration.
- 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. Iodine, being the largest atom, has the lowest electronegativity among the halogens listed.
- Which of the following elements has the highest melting point?
a) Oxygen (O)
b) Nitrogen (N)
c) Sulfur (S)
d) Phosphorus (P)
Answer: c) Sulfur (S)
Explanation: Sulfur has a higher melting point due to its larger atomic size and molecular structure (S₈), which requires more energy to break the bonds compared to the smaller molecules of oxygen (O₂) and nitrogen (N₂).
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