Final answer:
Groups on the periodic table indicate the number of electrons in the outermost shell of an atom. Electrons are found on the outside shell, and in a neutral atom, they equate in number to the protons within the nucleus. The correct answer is option C: Electrons, Protons.
Step-by-step explanation:
The student's question revolves around understanding what groups on the periodic table help us determine regarding an atom, and which particles are found on the atom's outside shell. When looking at the periodic table, each column or 'group' helps to indicate the total number of electrons present in the outermost shell of the atoms in that group.
The answer to this question is therefore option C: Electrons, Protons. Electrons are found on the outside shell of an atom, and their number in a neutral atom is equal to the number of protons, which are found in the nucleus. For example, hydrogen with one electron and one proton is known as a hydrogen atom, while helium has two electrons, two protons and generally two neutrons.
The mass number (A) of an atom is the sum of the number of protons (p+) and neutrons (n) in the nucleus. The electron orbitals are the defined spaces around an atom's nucleus where electrons are most likely to be found. Understanding the periodic table's organization, which is based on the number of protons (which equals the number of electrons in a neutral atom), helps in knowing how these electrons are distributed amongst the shells.