“Periodic Table” MCQ with Answer Explanation.

41. Which of the following elements is most likely to form a +3 oxidation state?
    A) Oxygen
    B) Nitrogen
    C) Aluminum
    D) Sodium
    Answer: C) Aluminum

Explanation: Aluminum (Al) commonly exhibits a +3 oxidation state by losing three electrons, forming Al³⁺ ions.

42. Which of the following statements is true about the lanthanides?
    A) They are all transition metals.
    B) They are f-block elements.
    C) They are found in Group 18.
    D) They have completely filled d-orbitals.
    Answer: B) They are f-block elements.

Explanation: Lanthanides are a series of 15 f-block elements from Lanthanum (La) to Lutetium (Lu), known for their similar chemical properties and are located in the f-block of the periodic table.

43. Which of the following elements has the greatest tendency to form cations?
    A) Nitrogen
    B) Phosphorus
    C) Sodium
    D) Chlorine
    Answer: C) Sodium

Explanation: Sodium (Na) readily loses one electron to form Na⁺ cations, demonstrating a strong tendency to form positive ions.

44. Which of the following elements is least likely to form a covalent bond?
    A) Carbon
    B) Hydrogen
    C) Oxygen
    D) Sodium
    Answer: D) Sodium

Explanation: Sodium (Na) typically forms ionic bonds by losing an electron rather than sharing electrons to form covalent bonds.

45. Which of the following elements has the highest metallic character?
    A) Lithium
    B) Beryllium
    C) Boron
    D) Carbon
    Answer: A) Lithium

Explanation: Metallic character decreases across a period from left to right. Lithium (Li) is the most metallic among the given elements.

46. Which of the following elements has a filled d-subshell in its ground state?
    A) Scandium
    B) Titanium
    C) Zinc
    D) Chromium
    Answer: C) Zinc

Explanation: Zinc (Zn) has the electron configuration [Ar] 3d¹⁰ 4s², indicating a filled d-subshell.

47. Which of the following elements is a gas at standard temperature and pressure (STP)?
    A) Nitrogen
    B) Sulfur
    C) Bromine
    D) Aluminum
    Answer: A) Nitrogen

Explanation: Nitrogen (N₂) is a diatomic gas at STP, whereas sulfur and bromine are solids and liquids, respectively, and aluminum is a solid metal.

48. Which of the following is a characteristic of nonmetals?
    A) High electrical conductivity
    B) Malleability
    C) Brittleness
    D) Lustrous appearance
    Answer: C) Brittleness

Explanation: Nonmetals are generally brittle in solid form, lack metallic luster, and have poor electrical conductivity.

49. Which of the following elements is an alkaline earth metal?
    A) Lithium
    B) Potassium
    C) Calcium
    D) Fluorine
    Answer: C) Calcium

Explanation: Calcium (Ca) belongs to Group 2, which consists of the alkaline earth metals known for their two valence electrons.

50. Which element is placed in Period 3 and Group 17 of the periodic table?
    A) Chlorine
    B) Bromine
    C) Iodine
    D) Fluorine
    Answer: A) Chlorine

Explanation: Chlorine (Cl) is located in Period 3 and Group 17, which is the halogen group.