Question

what is the energy required to remove an electron from an atom in the gaseous state called?
shielding energy
ionization energy
electronegative energy
nuclear energy

Explanation:

Ionization energy is defined as the energy required to remove an electron from an atom in the gaseous state. Shielding energy refers to the reduction in attraction between electrons and the nucleus due to inner - shell electrons. Electronegative energy is not a standard term (electronegativity is a measure of an atom's tendency to attract electrons in a chemical bond). Nuclear energy is related to energy from nuclear reactions (like fission or fusion).

Answer:

Ionization energy.