The ratio of potential energy of electron in the third orbit of Li2+ ion to the kinetic energy ofelectron in the fourth orbit of He+ ion is

The potential energy (PE) of an electron in an atom is given by the formula:

PE = -13.6 * Z^2/n^2 eV

where Z is the atomic number and n is the principal quantum number (orbit number).

For Li2+ ion, Z = 3 (as it has 3 protons) and n = 3 (as the electron is in the third orbit). Substituting these values in the formula, we get:

PE (Li2+, n=3) = -13.6 * 3^2/3^2 = -13.6 eV

The kinetic energy (KE) of an electron in an atom is given by the formula:

KE = 13.6 * Z^2/n^2 eV

For He+ ion, Z = 2 (as it has 2 protons) and n = 4 (as the electron is in the fourth orbit). Substituting these values in the formula, we get:

KE (He+, n=4) = 13.6 * 2^2/4^2 = 3.4 eV

Therefore, the ratio of potential energy of electron in the third orbit of Li2+ ion to the kinetic energy of electron in the fourth orbit of He+ ion is -13.6/3.4 = -4.