Chapter 2 and 3

Chapter 2 and 3 - HP 320 Matter and Elements Matter =...

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Life HP 320 Matter and Elements ! Matter = anything that takes up space, i.e. the material that the universe is made up of ! Elements = the substances that make up all matter Chemical Elements in the Body (Table 2-1) ! Major elements : ~ 99.3% ! Oxygen (O) ! Carbon (C) ! Hydrogen (H) ! Nitrogen (N) ! Minor elements : ~ 0.7% ! Calcium (Ca) ! Phosphorus (P) ! Chlorine (Cl) ! Magnesium (Mg) ! Potassium (K) ! Sodium (Na) ! Sulfur (S) ! Trace elements: ~ 0.01% ! e.g. chromium, cobalt, copper, fluorine, iodine, iron, silicon, Chemical Elements in the Body Atomic Structure ! Nucleus ! protons (+vely charged) ! neutrons ( neutral) ! Electrons: -vely charged particles in orbitals ! determine how the atom will react chemically ! # Protons = # Electrons ! overall an atom is electrically neutral (0) ! Weight of Protons ~ Weight of Neutrons Properties of Atoms ! Atomic # = # of protons (also equal to # of electrons, since # protons = #electrons) ! Atomic mass (wt.)= wt. protons + wt. neutrons ! The Hydrogen (H) atom is the simplest atom with only 1 proton, 1 electron, and NO neutrons
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! Multiple forms of the same atom having the same # of Properties of Atoms ! Energy levels = distances from the nucleus of an atom, in which its electrons orbit ! More distant energy levels can hold > 8 electrons, but, atoms are stable (non-reactive) when they have 8 electrons in their outermost energy level ! The electrons in the outermost level give the atom its chemical properties Properties of Atoms ! If the outermost energy level has > 4 e - but < 8 (the stable #), the atom normally gains e - to complete this level ! -vely charged ion ! If the outermost energy level has < 4 e - , the atom normally loses e - ! +vely charged ion ! Valence = the # of electrons lost or gained by atoms in a chemical reaction ! Valence level = the outermost energy level which determines the combining properties of the element Ions ! Atoms which gain or lose an electron ! If an atom loses an electron " + vely charged ion ! CATIONS = +vely charge ions, e.g. ! sodium ion = Na+ ! calcium ion= Ca++ ! If an atom gains an electron " - vely charged ion ! ANIONS = -vely charged ions, e.g. ! chloride ion = Cl - ! carbonate ion = HCO 3 - ! Ions have the ability to conduct electricity when dissolved in water (i.e. electrolytes) ! Molecule: 2 or more atoms unite ! may be identical (e.g. O 2 ) or different (H 2 O) ! Compounds: 2 or more different elements unite ! a molecule is the smallest stable part of a compound that still retains the properties of that compound Water ! Universal solvent (the body’s main solvent) ! ! Distributes heat throughout the body ! Cools the body via evaporation ! Necessary in metabolic reactions ! Body has ~ 40 liters (10.56 gallons) of body water ! % of body water decreases ( # )
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This note was uploaded on 09/22/2008 for the course HP 320 taught by Professor Islam during the Spring '08 term at USC.

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Chapter 2 and 3 - HP 320 Matter and Elements Matter =...

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