BIOL 1107 Lecture Notes - Lecture 1: Valence Electron, Chlorine, Electronegativity
Document Summary
Electrons move around the atomic nuclei in specific regions called orbitals. Each orbital can hold up to 2 electrons. Orbitals are grouped into levels called electron shells. Electron shells are numbered, with smaller numbers closer to the nucleus. The electrons on the outermost shell are called the valence electrons. These valence electrons are the only electrons who can react with one another to create new substances. Elements commonly found in organisms have at least one unpaired valence electron. The number of unpaired electrons is called the valence. Orbitals are areas which determine how an atom reacts with other atoms. There are elements of chemisty in biology. Nitrogen incorporated itself in a huge way in protiens. Chlorine and sodium are in our nervous systems-more specifically in the membrane potentials. However, life did not chose fluorine (why?) Unfilled electron orbitals allow formation of chemical bonds, and atoms are most stable when each orbital is filled.
