Question

Which shells are called penultimate and prepenultimate shells?

Answer 1

Understanding the concept:

• In an atom, the electrons are dispersed among the different shells surrounding the nucleus.
• The valence shell is the last shell or outermost nucleus shell.

Explanation of penultimate and pre-penultimate shell:

• The final electron in an element's atom moves to the valence shell, which is the atom's outermost shell.
• Penultimate shell refers to the shell inner to the valence shell, and pre-penultimate or anti-penultimate shell refers to the shell inner to a penultimate shell.
• Penultimate & pre-penultimate shells are filled in the case of representative elements, while valence shells are the only ones that are incomplete.
• In the case of transitional elements, the valence & penultimate shells both are incomplete.
• The last three shells—valence, penultimate, and pre- penultimate—of inner transition elements, also known as f block elements, are incomplete
• In a sodium element, valence shell, penultimate shell, and pre -penultimate shell is shown as,

•