Name:
1. Three elements having a single electron in their outermost shell.
2. Three elements with filled outermost shell.
3. Three elements having 7 electrons in their outermost shell.
1. Hydrogen (H), Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), cesium (Cs) and francium (Fr)
2. Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe)
3. Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I)