Question

Consider two hypothetical elements, X and Z. Element X has an electron affinity of 300 kj/mol and element Z has an electrona ffinity of 75 kj/mol. If you have an X- ion and a Z- ion from which ion would it require more energy to remove an electron? Explain. I think it's X but can someone give me a well formulated explanantion or explanations. Thank you!

Answer 1

As per the definition of the electron affinity, it is the amount of energy released when an electron is added to a neutral atom in the gaseous state.

This is reverse to the ionization energy of corresponding negative ion.

Kindly note that energy of a free electron is zero. When it is added to an atom, it releases energy. (energy of an electron in atoms are always negative). To remove an electron also that much energy should be supplied.

Thus, we have to give 300 kJ/mole energy to release an electron from X- and 75 kJ to remove an electron from Z-.

Thus X- requires more energy to ionize.