LIFESCI 7A Midterm: Biology LS 7A Midterm 1 Study Guide Weeks 1-3
Document Summary
Learning goal: understand basic concepts in chemistry needed to appreciate the structure and function of biological molecules and cells: describe the structure of an atom and the arrangement of electrons in energy shells. Atoms consist of three subatomic particles: protons, neutrons, and electrons. A proton has a positive charge and a neutron has no charge. Both protons and neutrons are found in the densely packed, positively charged nucleus. The nucleus contains essentially all of the mass of the atom. Electrons carry a negative charge and are found in electron shells surrounding the nucleus. The mass of the electron is considered to be negligible. Electrons within an atom can be assessed according to the shell, subshell, and orbital to which they are assigned and increase in size and energy as they get further away from the nucleus. Rest have maximum 8 electrons: define and relate the terms electronegativity and polarity. Electronegativity is a measure of how much an atom attracts electrons.
