Question

Atomic number of three elements A, B, and C are 3, 9, and 11. Write with reason, the chemical properties of which two elements are alike?​

Answer 1

Solution :

Let us first write down the electron configurations of these three elements:

(this is provided in the picture area...take a look at it)

We know that the elements having the same number of valence electrons (which belong to the same group of the periodic table), show similar chemical properties. Here, the elements A and C will show similar chemical properties because their atoms contain the same number of valence electrons (1 valence electron each) in their atoms.