CHEM 1070 Chapter Notes - Chapter 4: Unified Atomic Mass Unit, Periodic Trends, Electric Charge
Document Summary
Each element is composed of tiny indestructible particles called atoms. All atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements. Atoms combine in simple, whole number ratios to form compounds. Ernest rutherford"s nuclear theory of the atom: Most of the atom"s mass and all of its positive charge are contained in a small core called the nucleus. Most of the volume of the atom is empty space through which the tiny, negate electrons are dispersed. There are as many negatively charged electrons outside the nucleus as there are protons inside the nucleus, so that the atom is electrically neutral. Nucleus: contains positively charged protons and neutral particles, neutron. Dense nucleus makes up more than 99. 9% of the mass of the atom, but occupies only a small fraction of its volume. Electrons are distributed through a much larger region, but don"t have much ass.
