Question

The element which belongs to 3^rd period and 14^th group in Modern periodic table is

• A. Aluminium
• B. Silicon
• C. Phosphorous
• D. Sulphur

Answer 1

The Correct Option is B

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

1. Understanding the s-block Elements:
S-block elements are those elements whose outermost electrons are in the s-orbital. These elements are found in the first two groups of the periodic table (Group 1 and Group 2). The s-block elements include the alkali metals and alkaline earth metals.

2. Analyzing the Given Atomic Numbers:

• Atomic numbers 5 and 6 correspond to Boron (B) and Carbon (C), which are not s-block elements.
• 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.
• Atomic numbers 7 and 8 correspond to Nitrogen (N) and Oxygen (O), which are not s-block elements.

Final Answer:
The pair of atomic numbers that indicates the s-block elements is 11 and 12 (Option C).