Which atom has two core electrons and one valence electron?
A) H
B) He
C) H and He
D) Li
E) All of the above

Question

Which atom has two core electrons and one valence electron? 
A) H 
B) He 
C) H and He 
D) Li 
E) All of the above

Quizplus · Accepted Answer

The question is asking for an atom that has two electrons in its innermost shell (core electrons) and one electron in its outermost shell (valence electron).

Option A (H) has only one electron and option B (He) has two electrons in its innermost shell, making it a noble gas with a full valence shell. Therefore, neither A nor B match the criteria.

Option C (H and He) is incorrect because H has only one electron in total and He has two core and two valence electrons, making it also a noble gas with a full valence shell.

Option D (Li) is the correct answer as it has two core electrons and one valence electron in its outermost shell.

Which Atom Has Two Core Electrons and One Valence Electron