Which of the following is the electronic configuration of a metallic element?

Correct answer: (d) 2, 8, 8, 2

Explanation

Configuration 2, 8, 8, 2 has 2 valence electrons, which atoms lose easily, a typical metallic trait.

This is calcium (Ca, atomic number 20), an alkaline earth metal in Group 2.

Configurations like 2,8,7 (7 valence electrons) belong to non-metals, which gain electrons instead.