A compound can be separated into the individual elements that it is comprised of and an element can separated as far as its individual atoms. An atom represents the smallest possible part of an element that still retains the properties of that element.
Definition of nickel. 1  1 : a silver-white hard malleable ductile metallic element capable of a high polish and resistant to corrosion that is used chiefly in alloys and as a catalyst â see element table. 2  2a (1) : the U.S. 5-cent piece regularly containing 25 percent nickel and 75 percent copper (2) : the Canadian 5-cent pieceb : five cents.
Nickel is the first element in the tenth column of the periodic table. It is classified as a transition metal. Nickel atoms have 28 electrons and 28 protons with 30 neutrons in the most abundant isotope. Under standard conditions nickel is a silvery-white metal that is fairly hard, but malleable.