I apologize for the incorrect information in my previous response. You are correct that hydrogen has only one valence electron, not two, and it does not possess any core electrons.
In atomic terms, valence electrons are the electrons present in the outermost energy level or shell of an atom, while core electrons are the electrons found in inner energy levels or shells. The number of valence electrons an atom has determines its chemical properties and reactivity.
Hydrogen, being the first element in the periodic table, consists of a single electron orbiting around its nucleus. This electron occupies the first and only energy level (shell) of hydrogen, and therefore, it is considered a valence electron. Hydrogen does not possess any core electrons since there are no inner energy levels or shells beneath its sole energy level.
To clarify, hydrogen has one valence electron and zero core electrons.