The valency of an element with atomic number 8 is :

Options

A. 7
B. 6
C. 2
D. 1

Explanation

To determine the valency of the element with atomic number 8, we can follow these steps:

### Step 1: Identify the Element
The atomic number 8 corresponds to the element Oxygen (O).

### Step 2: Determine the Electronic Configuration
For an element with atomic number 8, the electronic configuration can be determined as follows:
- The first shell (K shell) can hold a maximum of 2 electrons.
- The second shell (L shell) can hold a maximum of 8 electrons.

Thus, the electronic configuration of Oxygen is:
- K shell: 2 electrons
- L shell: 6 electrons

So, the complete electronic configuration is 1s² 2s² 2p⁴, which shows that Oxygen has 6 electrons in its outermost shell (valence shell).

### Step 3: Determine the Valency
Valency is defined as the number of electrons an atom can lose, gain, or share to achieve a stable electronic configuration (octet).

In the case of Oxygen:
- It has 6 electrons in its valence shell.
- To achieve a stable octet (8 electrons), it needs to gain 2 more electrons.

### Step 4: Conclusion
Since Oxygen needs to gain 2 electrons to complete its octet, its valency is 2.

Thus, the valency of the element with atomic number 8 (Oxygen) is **2**.