How does the metallic and non-metalic character vary on moving from left to right in a period?

Answer

A

Explanation

As we move from left to right in a period, the number of valence electrons increases by one at each succeeding element but the number of shells remains same. Due to this effective nuclear charge increase. More is the effective nuclear charge, more is the attraction between nuclei and electron.
Hence, the tendency of the element to lose electrons decreases, this result in decrease in metallic character. Furthermore, the tendency of an element to gain electrons increases with increases in effective nuclear charge, so non-metallic character increases on moving from left to right in a period.