Answer:
Lithium
Explanation:
Lithium is in group 1 and group 1 elements have only 1 valence electron on their outer shell.
Beryllium is in group 2 so it has 2 valence electrons.
Boron is in group 3 so it has 3 valence electrons.
Carbon is in group 4 so it has 4 valence electrons.
