Which element has 6 valence electrons? The Periodic Table O A. Carbon (C) O B. Barium (Ba) O C. Selenium (Se) O D. Lithium (Li)

c) selenium

Explanation:

Selenium is present in group sixteen.

It has six valance electrons.

Its atomic number is 34.

Atomic mass of selenium is 78.96 amu.

Electronic configuration pf selenium:

Se₃₄ = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁴

we can see there are six valance electrons are present in selenium (4s² 4p⁴).

Valance electrons are those electrons which are present in outer most  electronic shell.

Other options are incorrect because,

There are  4 valance electrons in carbon.

2 valance electrons of barium.

one valance electron of lithium.

a electronegativity decreases beacuse the size of nucleus is bigger.