The atomic number of nickel is 28, which means that it has 28 protons in its nucleus. It also has 28 electrons and 31 neutrons.
Nickel is considered a transition metal. The defining characteristic of a transition metal is that it uses multiple orbitals for the electrons it employs to attract other elements. This means that the outer shell is sometimes not filled, even when the metal forms a stable ion. Nickel is conductive for electricity and heat, and it can be magnetized. Though a "nickel" can be found in many pockets, the coin actually contains only about 25 percent nickel.