Final answer:
For nonmetals in the second period, the number of unpaired dots on Lewis electron dot diagrams indicates the number of valence electrons, which determines an atom's bonding capacity.
Step-by-step explanation:
For nonmetals in the second period, the number of unpaired dots in the Lewis electron dot diagrams indicates the number of valence electrons. These unpaired electrons are significant since each one can potentially form a chemical bond. In the context of the periodic table, as we look at the elements in the second period, we start with Lithium (Li) which has one valence electron, and move towards Neon (Ne), which has eight valence electrons. The electron dot diagrams are particularly helpful in predicting how many bonds an atom can form, as elements tend to share their unpaired electrons through bonding.
While it can be tempting to associate unpaired dots with other properties such as ionization energy, atomic radius, or electronegativity, these are related to but not directly indicated by the unpaired electrons in the diagrams. Ionization energy and electronegativity generally increase across a period, while atomic radius decreases across a period. However, it is specifically the count of unpaired electrons in the Lewis diagram that indicates the number of valence electrons.