Biology 2485B Lecture Notes - Lecture 3: Environmental Science, Chemical Substance, Atomic Number
9 Oct 2014
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Document Summary
Matter cannot be created or destroyed: all of the material in the universe that has mass and occupies space, whether solid, liquid, gas, is termed matter. Cations: ions that form when an atom loses electrons and therefore carry a positive charge. Anions: ions that gain electrons and therefore carry a negative charge. Atoms bond to form molecules and compounds: atoms can link chemically to form molecules, combinations of 2 or more atoms. Compounds: a molecule composed of atoms or 2 or more different elements ex. H2o: atoms bond, or combine chemically, because of an attraction for one another"s electrons. Covalent bonds: when atoms in a molecule share electrons: atoms in some covalent bonds share electrons unequally, with one atom exerting a greater pull. Ionic bonds: electrons are transferred from one atom to another: this causes charged ions, elements, molecules, and compounds can also come together in mixtures without chemically bonding or reacting.
