Electron gain enthalpy of an element is a measure of its atom's ability to accept an electron to from an anion. It is defined as the enegry change (i.e., enegry released or absorbed) when an electron is accepted by an isolated atom in the gaseous state in the_________of the free atom.

Options

A. ground state
B. first excited state
C. second excited state
D. third excited state

Answer

A

Explanation

Energy change is measured when an electron is added to the lowest enegry unoccupied orbital, i.e., ground state of atom. A positive enegry change means enegry is aboserbed, and a negative enegry change means enegry is relased. However, electron gain enthalpies are generally negative becuase enegry is usually relased when a neutral atom adds an electron.