What element have 5 electron shells and 6 valance electrons

Tellurium

Explanation:

It is stated that element have six valence electron thus the given element must be belongs to oxygen family.

There are five members present in oxygen family.

Oxygen, sulfur, selenium, tellurium, polonium

Electronic configuration of oxygen:

O₈ = [He] 2s² 2p⁴

It means given element is not oxygen because it has two electronic shell.

Electronic configuration of sulfur:

S₁₆ = [Ne] 3s² 3p⁴

It means given element is not sulfur because it has three electronic shell.

Electronic configuration of selenium:

Se₃₄ = [Ar] 3d¹⁰ 4s² 4p⁴

It means given element is not selenium because it has four electronic shell.

Electronic configuration of tellurium:

Te₅₂ = [kr] 4d¹⁰ 5s² 5p⁴

The given element is tellurium because it has six valence electrons and five electronic shell.

the answer is 303.15 or 303