Lithium atoms contain two core (1s) electrons and one valence (2s) electron
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
Lithium atoms contain two core (1s) electrons and one valence (2s) electron. The average distance of a 1s electron from the nucleus is approximately 0.30 Å, whereas the average distance of the 2s electron is about 1.50 Å. The experimentally measured ratio of the second to the first ionization energy of Li is 14.
(a) Using the values given, compute the ratio of the electrostatic attractions experienced by a 1s electron and by the 2s electron in a Li atom, assuming complete shielding of the nuclear charge by the core electrons for the 2s electron and no shielding for a 1s electron.
(b) Compare the ratio obtained in part (a) to the experimental ratio of ionization energies. Propose one significant reason for any discrepancy between the two ratios.
(c) Qualitatively predict how the ratio you calculated in part (a) would change if the average distance of the 2s electron were halved while all other factors remained constant. Justify your prediction.