This is
element number 29 on the
periodic table. As you can deduce from its
atomic number, it has 29
protons and 29
electrons and its most common
isotope contains 24
neutrons to give it an average
atomic mass of 63.546
amu. It has a
Ground state configuration of [Ar]4s
13d
10 and is one of those elements that does not like to conform to
Aufbau's rules of simple
orbital filling.
Copper is also a main component in the alloy that makes the penny, but it is also used, sometimes, in piping to help reduce the amounts of lead in drinking water. Unlike other metals, copper is not replaced by hydrochloric acid. In order to dissolve a penny in acid, it must be placed in nitric acid where it then dissolves into copper ions and changes the liquid's color from colorless to blue.