Question

Which of the following pair of atomic numbers indicates the s-block elements?

• A. 5, 6
• B. 9, 10
• C. 11, 12
• D. 7, 8

Answer 1

The Correct Option is C

To solve the problem, we need to identify which pair of atomic numbers corresponds to s-block elements.

1. Understanding s-block Elements:
The s-block elements are those whose outermost electrons are in the s-orbital. These elements are found in the first two groups of the periodic table, which include:

• Group 1: Alkali metals (e.g., lithium, sodium)
• Group 2: Alkaline earth metals (e.g., magnesium, calcium)

2. Identifying the s-block Elements Based on Atomic Numbers:

• Atomic number 5 corresponds to boron (B), which is not an s-block element.
• Atomic number 6 corresponds to carbon (C), which is not an s-block element either.
• Atomic numbers 9 and 10 correspond to fluorine (F) and neon (Ne), which are not s-block elements.
• Atomic numbers 11 and 12 correspond to sodium (Na) and magnesium (Mg), both of which are s-block elements.

Final Answer:
The correct answer is (C) 11, 12.