BSC 108 Lecture Notes - Lecture 2: Radionuclide, Subatomic Particle, Covalent Bond
9 May 2017
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Document Summary
Elements and atoms: element: substance which cannot be broken down into other substances by chemical reactions, 92 naturally occurring elements (103 total, atom: the smallest unit of an element that has all its properties. Chlorine cl: trace elements are essential for life. Fluoride in the water: there has been a sharp decline in tooth decay in the last few decades. Fluoride-containing chemicals have been added to drinking water and dental products: the use of fluoride in drinking water illustrates the point that organisms are chemical systems. Harmful: some elements are harmful to life. Ex: cadmium: has been found in some children"s trinkets, a known carcinogen. Subatomic particles in atoms: protons: positively charged, neutrons: no charge, electrons: negative charge. Characteristics of atoms: protons and neutrons in nucleus, electrons orbit, may occupy different energy levels, elements differ in the number of subatomic particles in their atoms. The number of protons = the atomic number.
