Periodic Classification of Elements (C10)

Write the number of periods and groups in the Modern Periodic Table. How does the metallic character of elements vary on moving (i) from left to right in a period, and (ii) down a group? Give reason to justify your answer.

Answer

Number of Periods: 7

Number of Groups: 18

Metallic character decreases along the period because effective nuclear charge increases on the valence electrons, hence decrease in tendency to lose electrons.

Metallic character increases down a group because effective nuclear charge experienced by valence electrons decrease, hence tendency to lose electron decreases.