化学电子问题~~大虾帮帮忙~
which of the following electron configurations correspond to an excited state?Identify the atoms and write the ground-state electron configuration where appropriate
a.1s2 2s2 3p1
b.1s2 2s2 2p6
c.1s2 2s2 sp4 3s1
d.[Ar]4s2 3d5 4p1
how many unpaired electrons are present in each of there species?
exicted state是什么?