Question

why the group and period number for beryllium same

Answer 1

Beryllium is the lightest member of the alkaline earth metals family. These metals make up Group 2 (IIA) of the periodic table. They include beryllium, magnesium, calcium, strontium, barium, and radium. Elements in the same column of the periodic table have similar chemical properties.

Answer 2

Group number and period number of an element depends on the valence shell electrons and number of shells respectively

Electronic configuration of Beryllium is 2,2

Beryllium has 2 electrons in its valence shell.

So if valence shell electrons are 1 or 2,the group number is 1 and 2 respectively

So the group number is 2.

Beryllium has 2 shells.

So the period number is 2.