In the figure given alongside :

(a) Name the shells denoted by A, B and C. Which shell has the least energy?

(b) Name X and state the charge on it.

(c) The above sketch is of …………… model of an atom.

(a) A is First energy level (K shell)

B is Second energy level (L shell)

C is Third energy level (M shell)

Shell K has the minimum amount of energy.

(b) X is the nucleus, it is positively charged.

(c) The above sketch is of Bohr's atomic model model of an atom.