Weak bonds: a bond, which is the result of very weak electrical attractions between atoms bearing partial electrical charges, is a hydrogen bond. A compound is a substance consisting of two or more different atoms, in specific proportions, bonded together in a specific pattern. A molecule is a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction. Molecular formula: a shorthand way to represent the types and numbers of different atoms present in a molecule: water: h2o, glucose: c6h12o6. Isomers: compounds that have the same molecular formula but a different arrangement of atoms. Larger the molecular formula, more potential for isomers: different types of isomers: 1 mole= the mass of a substance equal to its gram molecular weight. 1 molar solution= a solution that contains one mole of a substance per liter of solution.