co02 - CHAPTER 2 BASIC CHEMISTRY Chapter Outline 2.1...

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CHAPTER 2 B ASIC C HEMISTRY Chapter Outline 2.1 Chemical Elements A. Matter 1. Matter takes up space and has mass. 2. All living and nonliving matter is composed of 92 naturally-occurring basic elements. 3. Elements cannot be broken down to substances with different chemical or physical properties. 4. Six elements (C, H, N, O, P, S) make up 98% of living things. B. Atomic Structure 1. Chemical and physical properties of atoms (e.g., mass) depend on the subatomic particles. a. Different atoms contain specific numbers of protons, neutrons, and electrons. b. Protons and neutrons are in nucleus of atoms; electrons move around nucleus. c. Protons are positively charged particles; neutrons have no charge; both have about 1 atomic mass unit of weight. d. Electrons are negatively charged particles. 2. The atomic mass of an atom is about equal to the sum of its protons and neutrons. 3. All atoms of an element have the same number of protons, the atom’s atomic number . C. The Periodic Table 1. The periodic table shows how various characteristics of atoms recur. 2. The table is arranged in order of atomic number, with periods in horizontal rows and groups in vertical columns. D. Isotopes 1. Isotopes are atoms with the same number of protons but differ in number of neutrons; e.g., a carbon atom has six protons but may have more or less than usual six neutrons. 2. A carbon with eight rather than six neutrons is unstable; it releases rays and subatomic particles and is a radioactive isotope. 3. Low levels of radiation such as radioactive iodine or glucose allow researchers to trace the location and activity of the atom in living tissues; therefore these isotopes are called “tracers.” 4. High levels of radiation can cause cancerous tissues and destroy cells; careful use of radiation in turn can sterilize products and kill cancer cells. E. Electrons and Energy 1. Electrons occupy an orbital at some level near or distant from the nucleus of the atom. 2.
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co02 - CHAPTER 2 BASIC CHEMISTRY Chapter Outline 2.1...

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