Question

The number of valence electrons in argon (Z=18) is

• A. 8
• B. 6
• C. 4
• D. 0

Answer 1

Answer: (A), (D)

0

The correct option is (A).

Explanation of correct option:

1. The electrons present in the outermost orbit i.e. in the valence shell (an outermost orbit or shell) of an atom is known as Valence electrons.
2. The atomic number (Z) of argon is 18 and the mass number is 40.
3. The number of protons= 18, the number of electrons= 18, and the number of neutron= 22 ( Atomic number - Mass number)
4. The electronic configuration of argon is: K L M
5. 2 8 8
6. In argon, K, L, and M shells are filled. Hence, argon has 8 valence electrons.

Explanation of incorrect option:

Option (D): This is the invalid option. As in the outermost shell, 8 maximum number of electrons can be accommodated.

Option (B): Oxygen, sulphur, etc. contains the 6 valence electron, not argon.

Option (C): Carbon, silicon, etc. contains the 4 valence electron, not argon.

Thus, The number of valence electrons in argon (Z=18) is 8.