valance electron of sodium and magnesium are (a) 1 and 2 (b) 1 and 3 (c) 1 and 4 (d) 1 and 5

Question:

valance electron of sodium and magnesium are 

(a) 1 and 2 

(b) 1 and 3 

(c) 1 and 4 

(d) 1 and 5 

Answer: option (a) 1 and 2

Explanation:

The electrons in the outermost shell are the Valence electrons. These are the electrons in An atom that can participate in a chemical Reaction. 

The electron configuration for sodium (Na) is: 

1s²2s²2p⁶3s¹ 

The outer energy level for this atom is n = 3, And it has one electron in this energy level. Therefore, Sodium has one valence Electrons. 

The electron configuration for magnesium is: 

1s²2s²2p⁶3s²

The outer energy level for this atom is n = 3, And it has two electrons in this energy level. Therefore, magnesium has two valence Electrons. So, Valance electron of sodium and magnesium Are 1 and 2 respectively. Hence, the correct answer is option (a) 1 and 2.

Hence the answer is (A) 1 and 2