Valence electrons are the electrons which are present in the outermost shell or valence shell of an atom & are responsible for the reactivity of any compound.Option (c) Nuclear mass which consists of Protons and Neutrons, does not affect the valence electrons because nuclear mass is so small in comparison to the atom, it is considered as negligible.

Valence principal quantum number (n)

The valence principal quantum number (n) represents the energy level or shell in which the valence electrons are located. It determines the distance of the valence electrons from the nucleus and, therefore, affects their energy. The higher the value of n, the farther the valence electrons are from the nucleus and the higher their energy. As a result, the chemical behavior of the element is influenced by the valence electrons, which are involved in bonding and reactions. Therefore, the valence principal quantum number (n) does affect the valence shell and the chemistry of the element.

Nuclear charge (Z)

The nuclear charge (Z) refers to the number of protons in the nucleus of an atom. It determines the positive charge of the nucleus and influences the attraction between the nucleus and the valence electrons. The greater the nuclear charge, the stronger the attraction between the nucleus and the valence electrons. This affects the energy required to remove or add valence electrons, as well as the size of the atom and its reactivity. Therefore, the nuclear charge (Z) does affect the valence shell and the chemistry of the element.

Nuclear mass

The nuclear mass refers to the total mass of the protons and neutrons in the nucleus of an atom. It does not directly affect the valence shell or the chemistry of the element. The nuclear mass primarily influences the overall mass and stability of the atom, but it does not have a significant impact on the behavior or properties of the valence electrons. Therefore, the nuclear mass does not affect the valence shell.

Number of core electrons

The core electrons are the electrons located in the inner energy levels or shells of an atom. They are not involved in bonding or chemical reactions and do not directly affect the valence shell or the chemistry of the element. The core electrons provide stability and contribute to the overall electron configuration of the atom, but their presence or absence does not significantly alter the behavior or properties of the valence electrons. Therefore, the number of core electrons does not affect the valence shell.

In conclusion, the valence principal quantum number (n), nuclear charge (Z), and number of core electrons all affect the valence shell and the chemistry of the element. However, the nuclear mass does not directly influence the valence shell or the chemistry of the element.