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.
a nickel in american usage is a five cent coin struck by the united states mint composed of 75 % copper and 25 % nickel the piece has been issued since 1866the silver half dime equal to five cents had been issued since the 1790she new copper nickel coin was legal tender for up to one dollar and would be paid out by the treasury in exchange for coin of the united states excluding the half cent cent and two cent it was redeemable in lots of $ 100 for banknotes fractional currency in denominations of less than ten cents was withdrawn