Sagot :
Answer:
4. Group 15,16,17,18. Part of the transition metal, Lanthanides, and actinides.
5. Examples include hydrogen (H), lithium (Li), and sodium (Na). Any element in group 18 has eight valence electrons (except for helium, which has a total of just two electrons). Examples include neon (Ne), argon (Ar), and krypton (Kr).