Ion charge for pdtwo elements in the second transition series (y through cd) have four unpaired electrons in their 3 + ions. what elements fit this description

Answer is: Technetium (chemical element with symbol Tc and atomic number 43) and rhodium (symbol Rh and atomic number 45).

1) Electron configuration of technetium:

₄₃Tc 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d⁵5s².

In 3 + ion three valence electrons are removed:

₄₃Tc³⁺ 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d⁴, four unpaired electrons are in 4d orbital.

2) Electron configuration for rhodium:

₄₅Rh 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d⁸5s¹.

In 3 + ion three valence electrons are removed:

₄₅Rh³⁺ 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d⁶, in 4d orbital four electrons are unpaired and two electrons are paired.