September 21, Ch 2 Notes. Sep 18 1:29 PM. Sep 18 12:55 PM. Color Your Periodic Table

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1 Color Your Periodic Table Alkali Metals Yellow Alkaline Earth Brown Transition Orange Lanthanide/Actinide Green Other Metals/Metalloids Purple Non metals Blue Noble Gases Red Sep 18 1:28 PM Sep 21 7:43 AM Chapter 2 CHEMISTRY OF LIFE Matter is anything that occupies space and has mass. Mass is the quantity of matter that an object has. Weight is defined as the force produced by gravity on mass. Weight will change on different planets, mass is the same. Of the 100+ elements that are identified, only around 30 are important to living things. Over 90% of mass of all living things is composed of combinations of: Oxygen Carbon Hydrogen Nitrogen Sep 18 12:55 PM Sep 18 1:28 PM Sep 18 1:29 PM Sep 18 1:29 PM 1

2 Simply Science Periodic Table Video Sodium in Water Description A small piece of metallic sodium is placed in a dish of water containing phenolphthalein on an overhead projector stage. The sodium reacts vigorously, melts, and sputters on the surface of the water as a sphere of continuously decreasing size until it has completely reacted. The moving sodium leaves a pink trail in the water. Alkali metals react with water. Lithium reacts. Sodium reacts very vigorously. Potassium and rubidium react still more vigorously. Cesium reacts explosively. The equation describing this reaction is: o 2 Na + 2 H 2O > 2 Na OH + H 2(g) This reaction is very exothermic. Sometimes the hydrogen produced catches fire with oxygen in the air. Using warm water promotes a vigorous reaction. This reaction is very exothermic. Sometimes the hydrogen produced catches fire with oxygen in the air. Using warm water promotes a vigorous reaction. Sep 18 1:29 PM Sep 21 7:47 AM ***Look at the periodic table handout Find the Atomic Number Top # Chemical Symbol (sometimes initials are from the Latin word) Atomic Mass Bottom # Elements are substances that cannot be broken down chemically into simpler kinds of matter. Atoms are the simplest particle of an element that retains all of the properties of that element. Safety Time! O H H Sep 18 1:30 PM Sep 16 11:43 AM The Nucleus of the atom makes up the bulk of the mass and consists of the Proton, which is positively charged, and the Neutron, which has no charge. The number of protons makes up the atomic number. The Atomic mass is the number of protons and neutrons. Q=Look up Sodium. What is it s symbol? What is the atomic number? How many neutrons does it have? Sep 18 2:15 PM Sep 18 2:15 PM 2

3 Electrons are negatively charged particles that orbit outside of the atom s nucleus. Electrons in different orbits create the Electron Cloud around the nucleus. They have very little mass. Each orbital level or energy level has a specific number of electrons that it can hold. The first level can only hold 2 electrons. The second level has four orbitals and can hold 8 electrons. Sep 18 2:15 PM Sep 18 2:19 PM Sep 18 2:19 PM Sep 18 2:25 PM Isotopes atoms of the same element that have different number of neutrons and atomic mass. Bohr Model: Look at the Group, Period, and Atomic Mass Lewis Dot: Just look at the Group for the Valence # Sep 18 2:25 PM Sep 21 7:49 AM 3

4 Compounds atoms of most elements easily combine in fixed proportions. H 2 O = 2 Hydrogens, 1 Oxygen and they always combine in a the same proportions. When elements combine, they may change their state. EX: O 2 & H 2 are gases in nature and liquid when they combine. Journal Entry: What particles can be smaller than protons, neutrons, and/or electrons? When and by whom were they discovered? At least one page explaining the answer to this question. Sep 18 2:21 PM Sep 21 7:52 AM Which Noble Gas would this be? When elements combine, they may change their state. EX: O 2 & H 2 are gases in nature and liquid when they combine. Atoms desire to have full energy levels. This makes them stable. They will readily bond to be stable. Noble & Inert gases already have a full VALENCE shell. Sep 21 8:03 AM Sep 21 7:53 AM Covalent Bonds two atoms share one or more electrons in their outermost level. Sep 18 2:24 PM Sep 18 2:30 PM 4

5 Ch 2 Notes An ionic bond is the force of attraction between the opposite charges of an ion. One element in an ionic bond loses electrons, and another element must gain the electrons. Some atoms lose electrons to make the outside energy levels become more stable. Many ionic compounds dissolve easily in water. The human body must keep a precise amount of ions in order to function properly, these ions are called electrolytes. Without the right concentration of electrolytes your nerve impulses can't travel to your brain. *When you sweat you lose electrolytes. Athletes drink certain drinks to keep the electrolytes balanced* Sep 18 2:35 PM Sep 18 2:31 PM Molecule simplest part of a substance that retains all the properties of that substance and can exist in a free state. Ques: How many bonds can an atoms of carbon have? In this animation you see two molecules, Potassium (K) and Iodine (I). The electron is transferring from the Potassium (K) ion to the Iodine (I) ion, which is what makes it an ionic compound. Potassium (K) losing an electron to Iodine (I). Potassium Iodide is used to treat thyroid problems in humans. Breakdown what these molecules are composed of; CH 4 NH 2 CH 2 COOH (NH 4 ) 2 SO 4 Sep 18 2:32 PM Sep 18 2:34 PM Energy Energy amounts in universe remain the same but energy is converted from one form to another. Energy is the ability to do work. Solids= fixed shape and volume Liquids=fixed volume but particles move Gas=move freely with in the limits of the container Chemical Reactions one or more substances change to produce one or more different substances. energy can be released energy can be absorbed bonds are broken new bonds can be formed Reactants > Products Sep 18 2:38 PM Sep 21 1:28 PM 5

6 Reversible Reactions can occur in two directions and use arrows in both directions to indicate reactions. Light Stick Demo Sodium Demo Chemical reactions require large amounts of Activation Energy to begin a process. A catalyst may be used to jump start a process by reducing the amount of activation energy needed. Humans and other living things us enzymes as a catalyst. Enzymes are a protein molecule. Oxidation Reduction Reactions A.K.A. Redox reactions Electrons are transferred between atoms. Oxidation reactant loses one electron and becomes positive Reduction gains one electron and becomes negative Activity*** pg 37 HMWK: pg 37 # 1, 3, 4, 5, 7 Sep 21 7:55 AM Sep 18 2:43 PM Water Play You are to use the tools provided and play with water. Magnesium Demo You are to observe water and record all the characteristics that you see. Do not worry about proper terms, just record what you can observe. Be creative. This is all to go in your journal. Sep 21 7:56 AM Sep 21 1:59 PM Polarity Not all covalent bonds share electrons equally. In water, the Oxygen has a greater pull on electrons. This creates a molecule that has regions that are more positive or negative. This uneven distribution creates a polar compound. Because of the polar qualities of water, it is a great solvent to dissolve polar substances such as sugar, ionic compounds, and proteins. Water can not dissolve non polar substances such as oils. Oct 7 10:37 AM Sep 18 2:44 PM 6

7 HYDROGEN BONDING the positively charged region of a water molecule is attracted to the negatively charged region of another water molecule. This positive / negative attraction is strong enough for water to cling to itself. Sep 25 2:50 PM Sep 25 11:28 AM Temperature Moderation: Water can absorb or release large amounts of energy in the form of heat with only a slight change in its own temperature. This is called specific heat. Energy is absorbed and breaks hydrogen bonds and energy is released as heat when bonds reform. Q: How does this relate to you on a hot day? Q: Why is liquid water denser than frozen water when most liquids are denser when they change to a solid state? Sep 27 11:35 AM Sep 25 11:33 AM Sep 21 11:53 AM Sep 27 11:48 AM 7

8 COHESION and ADHESION Cohesion is an attractive force that holds molecules of a single substance together. Water has a surface tension because of the hydrogen bonding of water. Q: What else can water do because of cohesion? Adhesion is the attractive force between two particles of DIFFERENT substances. The example is the glass rod and stream of water. Q: What is capillarity and what role does it play with adhesion and cohesion? Pg. 41 Polar Covalent Bonding an H2Obond.shtml If Bonds were Dogs schweiz2.ch/chemie/simulationen%20chemie/bindung/bindung% 20Hundeanalogie.htm Sep 27 11:35 AM Sep 18 2:41 PM SOLUTIONS a mixture one or more substances uniformly distributed in another substance. It can include solids, liquids, and gases. A SOLUTE is a substance dissolved in the solvent. The SOLVENT is the substance in which the solute is dissolved. SOLUTIONS can vary in their CONCENTRATION or amount of solute dissolved in a given solvent. If it is a saturated solution, then no more solute can be dissolved. AQUEOUS SOLUTIONS: have water as a solvent. Most solutions in the body occur with water as the solvent. ACIDS & BASES Ionization of water water moves about and they bump into one another. Some of the collisions are strong enough to result in a chemical change. One water molecule loses a proton and the other gains this proton. H 2O H + + OH The OH ion is known as the Hydroxide ion. The free H + ion can react with another water molecule. H + + H 2O H 3O + The H 3O + ion is known as the Hydronium ion. Alkalinity (or ph) is a measure of the amounts of Hydronium ions vs Hydroxide ions dissolved in a solution. Sep 27 11:35 AM Sep 27 11:38 AM If the Hydronium and Hydroxide are equal, the solution is said to be neutral and should have a ph of? ACIDS more Hydronium ions. It may have a sour taste and will be corrosive to some materials. BASES more Hydroxide ions. It is then alkaline. It will have a bitter taste, feel slippery. ph scale ranges from Most acidic weak acid Neutral Weak base Strong Base ph is measure on a logarithmic scale and therefore a change in ph unit reflects a 10 fold change. BUFFERS chemical substances that can neutralize small amounts of either an acid or base. Sep 27 11:38 AM Sep 27 11:43 AM 8

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