The Atom is the smallest component of any material, and all materials have different atomic structure. According to the Bohr model, the atom consists of a nucleus and orbiting negative charges, called electrons. The electrons are orbiting the nucleus att different layers (energy levels).The nucleus of an atom consists of positively and uncharged particles, called protons and neutrons. Copper is a metal commonly used in electrical circuits, and its Bohr model can be seen in the following figure.
The copper atom consists of 29 protons, 35 neutrons, and 29 electrons that orbit the nucleus. The neutrons orbit the nucleus at four different energy levels, where the electrons at the highest level are called valence electrons. The copper atom has only one valence electron, and this electron has a weaker bond to the nucleus compared to the electrons at lower energy levels. The valence electron can become a free electron if it receives enough thermal energy. A free electron will break away from the nucleus and move freely in the metallic material. It's because of the free electrons that copper is often used in electronics. Free electrons often makes the material a good conductor.
last edited: 2017.01.13