“Periodic Table” MCQ with Answer Explanation.

11. The element with the lowest electronegativity is:
    A) Helium
    B) Francium
    C) Lithium
    D) Fluorine
    Answer: B) Francium

Explanation: Electronegativity decreases down a group. Francium, being in the bottom left corner of the periodic table, has the lowest electronegativity.

12. Which of the following elements has the highest electron affinity?
    A) Fluorine
    B) Chlorine
    C) Bromine
    D) Iodine
    Answer: B) Chlorine

Explanation: While fluorine is more electronegative, chlorine has the highest electron affinity due to its larger atomic size, allowing it to accommodate the extra electron more easily than fluorine.

13. Which of the following trends occurs as you move across a period from left to right?
    A) Atomic radius decreases
    B) Ionization energy decreases
    C) Metallic character increases
    D) Electronegativity decreases
    Answer: A) Atomic radius decreases

Explanation: As you move across a period from left to right, the atomic radius decreases due to increased nuclear charge pulling the electrons closer to the nucleus.

14. The elements of which group in the periodic table are known as the alkali metals?
    A) Group 1
    B) Group 2
    C) Group 13
    D) Group 17
    Answer: A) Group 1

Explanation: Group 1 elements are known as alkali metals. They are characterized by having one electron in their outermost shell, making them highly reactive.

15. Which element belongs to the same group as carbon?
    A) Nitrogen
    B) Silicon
    C) Oxygen
    D) Phosphorus
    Answer: B) Silicon

Explanation: Silicon (Si) is in the same group as carbon (Group 14), meaning they both have four electrons in their outermost shell and share similar chemical properties.

16. Which of the following elements is a metalloid?
    A) Sulfur
    B) Sodium
    C) Boron
    D) Chlorine
    Answer: C) Boron

Explanation: Metalloids have properties of both metals and nonmetals. Boron (B) is a metalloid and lies along the diagonal dividing line between metals and nonmetals in the periodic table.

17. Which of the following blocks in the periodic table contains the lanthanides?
    A) s-block
    B) p-block
    C) d-block
    D) f-block
    Answer: D) f-block

Explanation: The lanthanides, along with the actinides, are found in the f-block of the periodic table. These are the elements in the two rows separated from the main body of the periodic table.

18. Which of the following elements has a diagonal relationship with lithium?
    A) Sodium
    B) Magnesium
    C) Beryllium
    D) Potassium
    Answer: C) Beryllium

Explanation: Lithium and beryllium show a diagonal relationship in the periodic table, meaning they exhibit similarities in properties despite being in different groups. This is due to their comparable charge densities.

19. Which of the following elements is a halogen?
    A) Argon
    B) Neon
    C) Bromine
    D) Krypton
    Answer: C) Bromine

Explanation: Halogens are found in Group 17 of the periodic table, and bromine (Br) is one of them. These elements are known for their high reactivity, especially with alkali metals.

20. Which of the following pairs of elements belong to the same period?
    A) Li and Be
    B) Na and K
    C) Mg and Ca
    D) F and Cl
    Answer: A) Li and Be

Explanation: Li (Lithium) and Be (Beryllium) belong to Period 2 of the periodic table. Elements in the same period have the same number of electron shells.