Why are valence electrons easier to remove from an atom than core electrons?

Answer 1

the force of attraction between then nucleus and the valence electrons is less than that between the nucleus and the core electrons

Answer 2

Valence electrons are further away from the nucleus and experience less attraction to the positively charged protons in the nucleus compared to core electrons. This makes valence electrons easier to remove from an atom. Core electrons are located closer to the nucleus and are more strongly attracted to the nucleus, requiring more energy to remove them from the atom.