Question

the _ will identify how many valence electrons for an atom. *
period number
group number
atomic number
mass number

how many electrons will rubidium need to gain or lose to be left with a full outer shell of valence electrons? * 2 points
rb
lose 1
gain 2
lose 3
gain 4
lose 5
gain 6
lose 7
gain 8

Explanation:

1. The group number of an element in the periodic - table indicates the number of valence electrons for main - group elements. For example, elements in group 1 have 1 valence electron, elements in group 2 have 2 valence electrons, etc.
2. Rubidium (Rb) is an alkali metal in group 1 of the periodic table. It has 1 valence electron. To achieve a full outer shell (noble - gas configuration), it will lose 1 electron.

Answer:

1. B. group number
2. A. lose 1