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.
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.