The energies of the orbitals in many elements have been determined. For the first two periods they have the following values:

(a) Why do the orbital energies generally become more negative on proceeding across the second period? 

(b) How are these values related to the ionization energy and electron attachment enthalpy of the elements? 

(c) Use these energy values to explain the observation that the ionization energies of the first four second-period elements are in the order Li B

Transcribed Image Text:

Element H He Li Be BUZOF C N L Ne 1s (kJ/mol) 2s (kJ/mol) 2p (kJ/mol) - 1313 -2373 - 520.0 -899.3 -1356 -1875 -2466 -3124 -3876 -4677 -800.8 -1029 -1272 -1526 - 1799 - 2083