Which statement describes the first ionization energy of an element?
The energy change when one mole of gaseous atoms gains one mole of electrons to form one mole of gaseous 1−1-1− ions.
The energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous 1+1+1+ ions.
The energy required to break one mole of covalent bonds in gaseous molecules.
The energy required to remove one mole of electrons from one mole of solid atoms to form one mole of solid 1+1+1+ ions.