2 The Composition of the Universe A. Element: a pure substance that cannot be broken down chemically into other kinds of matter.1. Ex: Oxygen, Carbon, Hydrogen, Nitrogen, Phosphorus
3 The Composition of the Universe B. Atom: simplest part of an elementC. Subatomic Particles: Parts of an atom1. Protons: positively (+) charged particlesa. Found in the nucleus of an atom2. Neutrons: neutral particles
4 The Composition of the Universe 3. Electrons: negatively charged particlesa. Found moving around the nucleus in energy levelsb. Valence electrons – electrons in the last shell or energy level of an atom** Hint: ** The number of valence electrons for an atom, is determined by the column (group) number it falls under on the Periodic Table of Elements. For example, an atom in the 3rd column, have 3 valence electrons.
5 The Composition of the Universe The Electron Energy LevelsBohr Model of Carbon:
6 The Composition of the Universe Lewis Dot Structure:
7 The Composition of the Universe D. How do you determine the number of protons?1. Equal to the atomic numberE. How do you determine the number of electrons?1. Equal to the # of protons (atomic number) in a stable atomF. How do you determine the number of neutrons?1. Equal to the Atomic Mass (rounded) – Atomic #
8 The Composition of the Universe The Electron Energy LevelsBohr Model of Carbon:
10 BondingA. All atoms “want” to be stable; if they do not have 8 valence electrons in their outer most shell, then they tend to undergo reactions to find stability 1. BONDS are then formed!
11 Occurs or Found Between? BondingType of BondOccurs or Found Between?How is the bond formed?Additional InfoIonicMetals and Non-metalsElectrons are transferred between atomsIon: positive & negatively charged atoms formed (Na+, Cl-)
12 BondingIs it easier for Potassium to gain or lose electrons to have a stable outermost ring of electrons?
16 Occurs or Found Between? BondingType of BondOccurs or Found Between?How is the bond formed?Additional InfoCovalent2 or more Non-metalsElectrons are shared between atomsCan be polar or non-polar bonds depending on electron sharing
17 Occurs or Found Between? BondingType of BondOccurs or Found Between?How is the bond formed?Additional InfoVan der waals forcesBetween molecules(intermolecular)Oppositely charged areas of molecules are attracted to each otherVery weak bonds; allows geckos to walk upside down; found between water molecules+-ATTRACTION OF DIFFERENT CHARGES BETWEEN MOLECULES
18 BondingEx: Gecko Foot – has half a million hair like projections that are divided into fibersForces form between the hairs on the feet and surface allowing the gecko to balance gravity
19 Building More Complex Substances B. Building More Complex Substances1. Compound: substance formed by the chemical combination of atoms from two or more elementsa. Ex: H2O (water), C6H12O6 (glucose), CO2 (carbon dioxide)The properties of the compound are different than those of the elements that create it!
20 Building More Complex Substances B. Molecule: the simplest form of a compound; when two or more atoms join1. Ex: O2 (oxygen gas), H2O (water)*All compounds are molecules, but not all molecules are compounds**
21 Mixing It Up…Solutions! A. Solution: a mixture in which one or more substances are uniformly distributed in another substance.1. Two major components a. Solute: substance dissolved into the solutionb. Solvent: substance in which the solute is dissolvedEx: WATER IS THE UNIVERSAL SOLVENT
22 Mixing It Up…Solutions! B. How do we analyze the strength of a solution? Concentration (amount of solute dissolved in solution)10g g g g g100mL mL mL mL mL
23 pH ScaleA. pH Scale: measures the concentration of hydrogen (H+) ions and hydroxide ions (OH-) in solutionRange of the Scale: 0-14
26 pH Neutral: Range: 7 H+ ions: [Equal] OH- ions: [Equal] Ex: WATER! What are the strong acids?What are the strongest bases?
27 The Chemistry of WaterA. COVALENT bonds: join hydrogen and oxygen that make up water1. Electrons are not shared EQUALLY!a. Oxygen has electronsb. Hydrogen only has 1 electronThe oxygen atom pulls the shared electrons towards its own nucleus and away from the hydrogen.
29 The Chemistry of WaterB. Polarity: the distribution of charges in atoms joined by a bond1. Polar compound: a molecule with an uneven pattern of charge or unequal sharing of electronsa. Ex: Water, Sugars, Proteins, DNA (good at dissolving things!)2. Non-polar compound: a molecule with an even pattern of charge or equal sharing of electronsa. Ex: Oxygen gas, fats, waxes++-
30 Polarity of Water C. Polarity of WATER 1. Causes water molecules to attract to each other or be “sticky” and form van der waals forces between thema. Hydrogen Bond: attraction holding two+ water molecules togetherPositive (H+) region of one water molecule is attracted to the negative (O-) region of anotherThese are weak bonds; they can be broken easily!
31 Why is hydrogen bonding important to life and biology? A. Creates cohesion of particles1. Attractive forces between particles of the same typea. Ex: Water “sticks” allowing striders to move across; Floating a paperclip on water
32 Polarity of WaterSurface Tension: created by cohesion; a force existing on the surface of a liquid, preventing the layer from being broken
33 Why is hydrogen bonding important to life and biology? B. Creates adhesion of particles1. Attractive forces between different/unlike substancesa. Ex: meniscus on a test tube
34 Why is hydrogen bonding important to life and biology? C. Capillary Action: water molecules move upward through narrow tubes against the force of gravity because of cohesion and adhesion1. Ex: flower, redwood tree
35 Why is hydrogen bonding important to life and biology? D. High Specific Heat Capacity & Heat of Vaporization:1. Water must gain or lose large amounts of energy (heat) to break the hydrogen bonds for any temperature change or evaporation to occur.a. Why is this important?Helps organisms maintain homeostasisHelps moderate climate/ocean water temperature
36 Why is hydrogen bonding important to life and biology? E. Water EXPANDS becomes LESS dense when it freezes!1. Why is this significant?a. Ice floats preventing the water from freezing solid and insulates the lower layers, allowing life to survive underneath it
37 Why is hydrogen bonding important to life and biology? F. Water is the universal solvent.1. Water dissolves more solutes than any other liquid.