Technetium Valence Electrons
Why technetium has 7
Technetium has 43 electrons, arranged as 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d5 5s2. Counting the 5s electrons plus the 4d electrons gives 7, the usual textbook convention for transition metals. Some courses count only the electrons in the outermost shell, which gives 2 for technetium; check which convention your class uses.
Technetium is a transition metal in group 7. Counting its outer s electrons plus the d electrons beneath them gives 7, the same as the group number.
What that means for bonding
Transition metals can lose different numbers of these electrons, which is why technetium shows several oxidation states (+1, +2, +3, +4, +5, +6, +7). When it forms a cation it loses the 5s electrons first.
Electrons per shell: 2, 8, 18, 13, 2. See the technetium electron configuration and orbital diagram or the full technetium data sheet.
Same group, same count
Technetium valence electrons FAQ
How many valence electrons does technetium have?
Technetium has 7 valence electrons. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁵ 5s²; the count is 2 outer s + 5 d electrons; 2 in the outermost shell. If your course counts only outermost-shell electrons, the answer is 2.
How do you find the valence electrons of technetium?
Technetium is a transition metal in group 7. Counting its outer s electrons plus the d electrons beneath them gives 7, the same as the group number.
How many bonds does technetium form?
Transition metals can lose different numbers of these electrons, which is why technetium shows several oxidation states (+1, +2, +3, +4, +5, +6, +7). When it forms a cation it loses the 5s electrons first.