BI110 Chapter 5: Module 5
Document Summary
Chemical bonds form because a full valence shell is more stable than a partly filled one. The valence shell is the outermost electron shell in an atom. There are several types of chemical bonds that are important in biological organisms: covalent bonds, ionic bonds, hydrogen bonds, and van der. The bonds vary in their strength that is, the amount of energy (in kcal/mol or kj/mol) required to form and break the bonds. A covalent bond forms when two non-metals share electrons. Non-metals have a valence shell that is at least half full but not completely filled. Non-metals tend to gain electrons to achieve a full valence shell. A single bond forms between two atoms that share one pair of electrons. A double bond forms between two atoms that share two pairs of electrons. Electronegativity is the ability of an atom to attract electrons. The greater the electronegativity, the more attraction an atom has for electrons.
