Chlorine because it lacks one valence electron to fill it's outer shell
A teratogen is an exposure (substance, organism or process) in pregnancy that has a harmful effect on the fetus. Teratogens can be diseases, medications, drugs and environmental exposures.
Answer:
What grade are you in. If i am older, I dont think you would be able to help me.
Explanation:
The answer is Ra
Atomic number for Be is 4
Atomic number for Mg 12
Atomic number for Ra 88
Atomic number for Ba 56