Which of the following elements has the same molecular mass as its atomic mass

To determine which element has the same molecular mass as its atomic mass, we need to consider the molecular formula of the element. 

The molecular formula of nitrogen is N₂, neon is Ne, oxygen is O₂, and chlorine is Cl₂.

The atomic mass of nitrogen is approximately 14 amu, and its molecular mass (molecular weight) is 28 amu (2 x 14), so it does not have the same molecular mass as its atomic mass.

For  O₂,, the atomic mass of oxygen is approximately 16 amu. Since oxygen exists as a diatomic molecule ( O₂,) in its standard state, the molecular mass (molecular weight) of  O₂, is 32 amu (2 x 16). Therefore, oxygen does not have the same molecular mass as its atomic mass.

For Cl₂ , the atomic mass of chlorine is approximately 35.5 amu. Like oxygen, chlorine exists as a diatomic molecule (Cl₂) in its standard state. The molecular mass of Cl₂ is therefore 71 amu (2 x 35.5). Therefore, chlorine also does not have the same molecular mass as its atomic mass.

Neon is a noble gas and exists as single atoms (Ne), so its atomic mass (approximately 20 amu) is the same as its molecular mass since it does not form molecules.