Question

what are ultimate and penultimate shell

Answer 1

The word 'penultimate' means that which comes next to last. Many use the term incorrectly. The penultimate shell would be the shell below the one presently being filled by electrons. If you have an electron shell configuration of 2, 8, 1, the shell configuration for Na, the penultimate shell would be the second shell. You could say that the 3rd shell, in this case, is the ultimate shell. 

Valence shell sometimes pronounce as ultimate shell. It is the outermost shell, which is farthest away from the nucleus and from which electron can be removed or added. 

Answer 2

there are two types of shell ultimate and penultimate shell

Explanation:

ultimate chal are also known as valence shell it has it is the outermost shell that contains the electrons

penultimate shell it is the shell having one less electron than ultimate shell which is n -1