alkali metals
Valence shell
The outer-most shell of an atom is called the valence shell. It is involved in forming chemical bonds with other atoms.
An egg with an outer hard shell is called the cuticle or bloom. It helps keep out bacteria and dust.
It is a shell, as in a cockle shell or oyster shell.
the shell
The outer shell of a watermelon is called the rind or peel. It is the tough outer layer that is typically green in color and protects the fruit inside.
The outer layer of a sea shell is called the exoskeleton or the shell's outer casing. It is composed of calcium carbonate and provides protection for the soft tissues of the animal inside.
Valence shell and Ultimate Shell
The outer shell of a plane can be called the skin. The smoother the skin the faster the plane passes through the air.
The outer covering of an egg is called the shell.
The outer shell of an atom is the valence shell, which contains the valence electrons.
The outer shell is called the valence shell