question_answer

The ground-state electronic configurations listed here are incorrect. Explain what mistakes have been made in each and write the correct electronic configurations. \[Al:\,1{{s}^{2}}2{{s}^{2}}2{{p}^{4}}3{{s}^{2}}3{{p}^{3}}\] \[B:1{{s}^{2}}2{{s}^{2}}2{{p}^{5}}\] \[F:\,1{{s}^{2}}\,2{{s}^{2}}\,2{{p}^{6}}\]

Answer:

                In \[_{13}Al,\,2p\] should be filled first before filling of 3s starts. Correct electronic configuration\[=1{{s}^{2}}\,2{{s}^{2}}\,2{{p}^{6}}\,3{{s}^{2}}3{{p}^{1}}\] In \[_{5}B,\] total electrons = 5. Hence, \[E.C.=1{{s}^{2}}2{{s}^{2}}2{{p}^{1}}\] In \[_{9}F,\] total electrons = 9. Hence, \[E.C.=1{{s}^{2}}\,2{{s}^{2}}\,2{{p}^{5}}\]