LIFESCI 2 Lecture Notes - Lecture 1: Molecular Orbital, Valence Electron, Atomic Mass
Document Summary
Elements: pure substances that cannot be broken down by chemical methods. Nucleus: made up of protons and neutrons. Atomic number: # of protons, specifies elements. Atomic mass: # p + # n, mass of atom. Isotopes: atoms with same # p but different # n. Because atoms are neutral, # p = #e- Ions: electrically charged atom because of lost or gain of e- Orbital: region around the nucleus in which e- move most of the time. Orbital closer to nucleus have less energy than those farther. Shell: or energy level at which several orbitals exist. Periodic table of elements: table that organized chemical elements, by mendeleev. Molecules: substances made up of two or more atoms. Chemical bond: attraction between atoms that holds them together. Determine ability of atoms to interact with each other. Molecular orbital: merge orbital from two atomic orbitals. Octet rule: molecules are most stable when they have full outer most orbitals (8e-)
