Answer:
1. Core electrons = 1s²; Valence electrons = 2s² and 2p³
2. Core electrons = 1s², 2s²,m2p⁶; Valence electrons = 3s² and 3p⁵
Explanation:
The electrons in an atom of an element are generally divided into two groups: the core electrons and the Valence electrons
Valence electrons are those electrons which are located of or found in the outermost shell or highest energy level of an atom. These valence electrons are the one that determine the chemical reactivity of an atom as they can participate in bond formation between atoms of the same element or with atoms of other elements. The valence electrons also, generally determine the group to which an element will belong to.
Core electrons on the other hand, are those electrons which are found within the innermost shell or lowest energy levels of the atom. They are strongly attracted to the nucleus of atom and do not take part in chemical bonding. However, they play the important role of shieldingnthe valence electrons from the positive charge of the nucleus thereby assisting the valence electrons in bond formation.
