Elements in the same group have similar properties because they

Check all apply

A. need the same number of electrons to fill their valence shells

B. have the same number of valence electrons

C. have the same number of electrons

D. have the same number of electron shells

A. need the same number of electrons to fill their valence shells

B. have the same number of valence electrons

Explanation:

Elements are distributed in groups and periods in a periodic table.

Elements that belong to same groups will show similar chemical properties because they have same number of valence electrons.

Example: Flourine, chlorine and bromine are elements which belong to Group 17. They have 9, 17 and 35 electrons respectively and contain 7 valence electrons each and need one electron to complete their octet.

The chemical reactivity of elements is governed by the valence electrons present in the element.

the independent variable, or the one that is intentionally manipulated is the speed.