Chapter 2 Outline-Small Molecules and the Chemistry of Life.docx
CAS BI 108
BI108 Chapter 2 Outline: Small Molecules and the Chemistry of Life
2.1—How DoesAtomic Structure Explain the Properties of Matter?
• An element only consists of one kind of atom
• Each element has a unique number of protons
• The number of neutrons differs among isotopes
• The behavior of electrons determines chemical bonding and geometry
Living organisms are composed of the same set of chemical elements as the rest of the
universe.An atom consists of a nucleus of proteins and neutrons, and a characteristic
configuration of electrons that determines the chemical properties.
2.2—How DoAtoms Bond to Form Molecules?
• Covalent bonds consist of shared pairs of electrons
• Ion attractions form by electrical attraction
• Hydrogen bonds may form within or between molecules with polar covalent bonds
• Hydrophobic interactions bring together nonpolar molecules
• Van der waals forces involve contact between atoms
Some form strong covalent bonds by sharing electron pairs. Unequal sharing produces
polarity. Other a