What can be inferred about the relationship between group number and outer shell electrons?

The group number in the periodic table of elements is directly related to the number of electrons present in the outermost shell of an atom for the main group elements. This holds true for groups 1 through 2 and 13 through 18. For instance, elements in Group 1 possess one electron in their outer shell, whereas those in Group 2 have two.

This characteristic of outer shell electrons is fundamental as it helps to predict the chemical properties and reactivity of the elements within that group. The number of outer shell electrons significantly influences how an element will bond with others, its ionization energy, and its electronegativity.

In contrast, the other options do not accurately represent the relationship between group number and outer shell electrons. The group number does not reflect atomic mass, which is a separate and distinct property related to the number of protons and neutrons in an atom's nucleus. The group number is also not indicative of the total number of electrons in an atom, as it only refers to those in the outer shell, and it doesn’t inform us about protons directly, since those are determined by the atomic number. Thus, the correlation between group number and the number of outer shell electrons is the reason for choosing the correct