which element has the same number of valence electrons as bromine?
A. krypton
B. selenium
C. potassium
D. Chlorine
why are sodium and potassium in the same group on the periodic table?
A. they have similar atomic wieghts
B. they are both hard and brittle
C. they have similar reactivity
D. they are both colorless
1 answer
gases at room temperature