Vocabulary Write the terms and definitions for each vocabulary word from sections 2-1, 2-2 and 2-3. Keep these pages in your vocabulary divider. Extra credit if you use this format (1/2 pt. for each term) Chapter 2 The Chemistry of Life 2-1: THE NATURE OF MATTER Atoms KeyC#1: What three subatomic particles make up atoms? The subatomic particles that make up atoms are protons, neutrons and electrons. Atom: basic unit of matter Protons: (+) charge Neutrons: no charge (neutral) Electrons: (-) charge How small is an atom?? http://ed.ted.com/lessons/justhow-small-is-an-atom Sketch figure 2-1 in your lecture notes. Elements and Isotopes What are elements? Let’s look at the periodic table of elements. (Appendix G) KeyC#2: How are all the isotopes of an element similar? Because they have the same number of electrons, all isotopes of an element have the same chemical properties. Facts to know about elements: Atomic number = # of protons Atomic mass = sum of protons & neutrons Isotopes differ in the number of neutrons Some isotopes are radioactive Let’s practice with some of the elements… Chemical Compounds What is a chemical compound? What are some examples of chemical compounds? Physical and chemical properties of a compound are usually very different from those of the elements from which it is formed. (i.e. Na & Cl) Chemical Bonds What holds atoms together? What is the key player in these bonds? KeyC#3: What are the two main types of chemical bonds? Ionic and covalent bonds Ionic bonds: transfer of electrons Covalent bonds: sharing of electrons Let’s look at figures 2-3 & 2-4 What are molecules? What does sharing electrons mean? Electrons will travel in both orbits 2 electrons = single bond 4 electrons = double bond Van der Waals forces: oppositely charged regions of molecules attract each other (intermolecular attraction) Chapter 2 The Chemistry of Life 2-2 PROPERTIES OF WATER The Water Molecule How is water neutral? Why are polar molecules attracted to each other? KeyC#1: Why are water molecules polar? What is the difference between COHESION and ADHESION? What are some examples of each? http://ed.ted.com/lessons/how-polaritymakes-water-behave-strangelychristina-kleinberg#watch Uneven distribution of electrons between the hydrogen and oxygen atoms. Oxygen (-) Hydrogen (+) Let’s draw! Solutions and Suspensions What is a mixture? Give me some examples of mixtures. Physically mixed, but not chemically combined Solution: solutes evenly distributed throughout the solvent (i.e. salt water) Solute is diluted Solvent is the disSOLVEr Suspensions: materials that do not dissolve but are suspended (i.e. blood) Acids, Bases, and pH What is the range of the pH scale? What is an acid? What is a base? Substance with more H+ ions than pure water. pH < 7 Substance with lower concentrations of H+ than pure water. pH > 7 What do buffers do?