A copper atom has how many electrons in its valence shell?

In a copper atom, the arrangement of electrons determines its chemical properties, particularly in terms of bonding and electrical conductivity. Copper has an atomic number of 29, which means it has 29 electrons. These electrons are arranged into energy levels or shells around the nucleus.

The electron configuration of copper is:

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹.

From this arrangement, we can see that the outermost shell (the valence shell) of copper comprises the 4s and 3d subshells. The 4s subshell contains one electron and the 3d subshell contains ten electrons, but for the purpose of identifying valence electrons, we focus on the highest energy level that participates in bonding.

Copper, therefore, effectively has one electron available in its valence shell for bonding processes. This single electron contributes to its ability to conduct electricity and forms the basis for its metallic properties. The presence of just one electron in the valence shell allows copper to easily lose that electron, which is a key factor in its conductivity and reactivity.