Question

Elements possessing atomic numbers, 3, 11, 19, 37 belong to__block.

• A. s
• B. p
• C. d
• D. f

Answer 1

The Correct Option is A

To determine the block to which elements with atomic numbers $3$, $11$, $19$, and $37$ belong, we need to analyze their electron configurations and placement in the periodic table.

1. Understanding Atomic Numbers and Electron Configurations:
The atomic number of an element corresponds to the number of protons in its nucleus, which also determines its electron configuration. Elements are classified into blocks (s, p, d, f) based on the subshell in which their outermost electrons reside.

2. Analyzing Each Element:

- Element with Atomic Number 3 (Lithium, Li):
The electron configuration of lithium is $1s^2 \, 2s^1$. The outermost electron is in the $s$ subshell.
Element with Atomic Number 11 (Sodium, Na):
The electron configuration of sodium is $1s^2 \, 2s^2 \, 2p^6 \, 3s^1$. The outermost electron is in the $s$ subshell.
Element with Atomic Number 19 (Potassium, K):
The electron configuration of potassium is $1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^1$. The outermost electron is in the $s$ subshell.
Element with Atomic Number 37 (Rubidium, Rb):
The electron configuration of rubidium is $1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^{10} \, 4p^6 \, 5s^1$. The outermost electron is in the $s$ subshell.

3. Identifying the Block:
All these elements ($\text{Li}$, $\text{Na}$, $\text{K}$, $\text{Rb}$) have their outermost electrons in the $s$ subshell. Therefore, they belong to the $s$ block of the periodic table.

4. Conclusion:
Elements with atomic numbers $3$, $11$, $19$, and $37$ belong to the $s$ block.

Final Answer: $ {\text{s}} $