Question

a student analyzes data showing the number of valence electrons for elements in period 3. which trend would the student observe as atomic number increases across the period? the number of valence electrons decreases from 8 to 1 as atoms become more metallic. the number of valence electrons increases from 1 to 8 then drops to 0 for the noble gas. the number of valence electrons increases from 1 to 8 as atoms become more non - metallic. the number of valence electrons remains constant at 8 for all elements in the period.

Explanation:

In the periodic table, for elements in a period, as the atomic number increases across a period (from left - to - right), the number of valence electrons increases. For Period 3 elements, sodium (Na) has 1 valence electron and argon (Ar) has 8 valence electrons. The noble gas at the end of the period has 8 valence electrons (except helium which has 2).

Answer:

The number of valence electrons increases from 1 to 8 as atoms become more non - metallic.