Answer:
1)Oxygen atoms have 8 electrons and the shell structure is 2.6. The ground state electron configuration of ground state gaseous neutral oxygen is [He]. 2s2. 2p4 and the term symbol is 3P2.
Explanation:
2)If the element were to become excited, the electron could occupy an infinite number of orbitals. However, in most texts the example will be the next available one. So for oxygen, it might look like this: 1s22s22p33s1 - where the valence electron now occupies the 3s orbital in an excited (i.e. not ground) state