Question

What is the trend of reactivity while moving up a group and from left of the modern periodic table towards right ?

Answer 1

For metals: Reactivity decreases as you go up in a group because the of the decreased tendency to donate electrons due to decrease in atomic size.

Across a period: Reactivity decreases because of the increase in ionization energy due to decrease in atomic size.

For non-metals: Reactivity increases on moving up in a group because the increased tendency to gain electrons due to decrease in atomic size up in a group.

Across a period:Reactivity increases because of increase in electronegativity due to decrease in atomic size.