Question

an atom has an atomic number of 9 a mass number of 19 and an electron configuration of 2-6-1 explain why the number of electrons in the second and third shells shows that this is in an excited state

Answer 1

You can tell that the atom is in the excited state because:

- Electron configuration should follow the 2-8-8-2 rule, meaning that the inner shell should be filled before the next shell can start holding electrons.

- Instead of the atom's electron configuration being in the ground state at 2-8-8-1, electrons from the second shell have jumped to the third.