They have scales and they rub off easily
Sound waves need different media in order to travel. This travels by the movement of the atom transferred to another up to its destination. The speed of sound is greatest in solids since the molecules of solid are closely packed together, followed by liquid and they are slowest in gases.
Ionic bonds occur when electrons are donated from one atom to another. Each type of atom forms a characteristic number of covalentbonds with other atoms. An example of that is a hydrogen atom with one electron in its outer shell forms only one bond, its out most orbital becomes filled with two electrons.
the outermost protons