2Composition of MatterMatter - everything in universe is composed of matter (“stuff”)Matter is anything that occupies space or has massMass – quantity of matter an object hasWeight – pull of gravity on an object
3Elements Pure substances that cannot be broken down Made of a single type of atom (group of atoms of the same type)More than 100 elements (92 naturally occurring)
4Elements Atomic # of an element Mass # of an element Therefore…. Equals the # of protons AND the # of electronsUnique for each elementMass # of an elementEquals the SUM of protons and neutronsTherefore….Protons + Neutrons = Mass #Mass # - Atomic # = Neutrons
5CHONPSAll living things are made up of 4 Biological macromolecules (which we will be talking about later).CarbohydratesLipidsProteinsNucleic AcidsBiological macromolecules are made almost entirely of just 6 elements:Carbon (C)Hydrogen (H)Oxygen (O)Nitrogen (N)Phosphorus (P)Sulfur (S)CHNOPSThe most important element is CARBON!
6Each element unique chemical symbol 96% of the mass of an organism is composed of 4 elements (carbon, hydrogen, oxygen (65%) and nitrogen “CHON”)Each element unique chemical symbolConsists of 1-2 lettersFirst letter is always capitalizedOther 4% consists of calcium (Ca), phosphorus (P) potassium (K), sulfur (S), sodium (NA), and other sevaral trace elements such as Fe (iron) needed to transport oxygen in your blood and Chromium (Cr) (needed for your cells to bread down sugars for usuable energy)
7Atoms Smallest and simplest piece of matter Atom have 3 subparticles: Protons (Positive +)Neutrons (Neutral 0)Electrons (Negative -)Millions of atoms could fit in a space the size of the period at the end of a sentence. And it would take you more than 1 trillion years to count the number of atoms in a single grain of sand.
8The Nucleus Middle of the atom (central core) Holds positive charged protons and neutral neutronsPositively chargedContains most of the mass of the atom
9The ProtonsAll atoms of a given element have the same number of protons#of protons = the atomic number# of protons (+’s) = # of electrons (-’s) (in a neutral atom)
10The NeutronsThe number varies slightly among atoms of the same elementDifferent number of neutrons produces isotopes of the same element
11Isotopes \ IsomersIsotopes = an element with the same # protons, but different # neutronsEx: C12 vs. C14Isomers = compounds with the same molecular formula, but different structures
12Atomic Mass Protons & neutrons are found in the nucleus of an atom Protons and neutrons each have a mass of 1 amu (atomic mass unit)The atomic mass of an atom is found by adding the number of protons & neutrons in an atomWhat is the atomic mass of an oxygen?
13Practice Problems! How many protons does a sodium (Na) atom have? How many neutrons does a fluorine (F) atom have?What is the atomic mass for oxygen (O)?What is the atomic number for phosphorus (P)?
14The ElectronsNegatively charged high energy particles with little or no massTravel at very high speeds in different energy levelsEnergy levels are different distances from the nucleus
15Energy LevelsElectrons in the same energy level are approximately the same distance from the nucleusOuter energy levels have more energy than inner levelsEach level holds only a certain number of electrons
16Electron Shell Electron Shell Shells: Inner most can hold at most 2 e-Outer most can hold at most 8 e-Third outer most can hold at most 8 e-Elements want to have full shells, because this makes them stable!Carbon (neutral)Atomic # = 6 6 total electrons2 electrons fill the inner most shell4 will be in the outer most shellThis means Carbon has 4 VALENCE electronsCan bond to 4 other atoms!
17Periodic TableElements are arranged by their atomic number on the Periodic TableThe horizontal rows are called Periods & tell the number of energy levelsVertical groups are called Families & tell the outermost number of electrons
19Compounds Most atoms do not exist by themselves Atoms combined with other atoms to form compounds
20CompoundsA compound is a pure substance made up of atoms of two or more elements2 types: molecules or ionic compoundsChemical formula shows the kind and proportion of atoms of each element that occurs in a particular compound
22Compounds What happens when the ratio of atoms changes? H20 vs. H2O2 When the ratio of elements in a compound changes, the physical and chemical properties change too
23MoleculesMolecule is two or more atoms held together by covalent bonds. Almost all of the substances that make up organisms, from lipids to nucleic acids to water, are molecules held together by covalent bonds.A compound is a type of molecule. All compounds are molecules, but all molecules are NOT compounds.Molecule Examples: H2O, O2, O3Compound Examples: NaCl, H2O
24Chemical Formulas 2H202 2H2O + O2 Subscript after a symbol tell the number of atoms of each elementH20 has 2 atoms of hydrogen & 1 atom of oxygenCoefficients before a formula tell the number of molecules3O2 represents 3 molecules of oxygen or (3x2) or 6 atoms of oxygen
25BondsMolecular “glue”Holds atoms together to form compoundsValence electrons are involved in bondingValence electrons = electrons on outer most energy level.Atoms are most stable when their outer most energy level is filled
26Bonding What holds atoms together? Atoms are held together by chemical bondsGoal: to fill outer electron shell…so atoms BOND together (share or give away/take electrons) to get a full outer shell2 main types:Ionic bondsCovalent bonds
27Bonds Single Double Triple Bonds SIZE decreases as you increase # of bondsBonds STRENGTH increases as you increase # of bonds
28Covalent BondingFormed when two atoms share one or more pairs of electrons. (‘co’ means ‘together’)When two or more atoms are joined by covalent bonds, we call this a moleculeVery strongSingle, double, triple bondsH = 1 bondO = 2 bondsN = 3 bondsC = 4 bonds
29Because positive and negative electrical charges attract each other ionic bonds form
30Ionic BondsFormed when one or more electrons are transferred from one atom to anotherAtoms lose or gain electronsIf an atom loses electrons becomes positively charged (+)If an atom gains electrons becomes negatively charged (-)Atoms that have gained or have lost electrons are ionsEx: Salt (NaCl)
31Cations & AnionsCation = when an atom loses an electron, it becomes more positively chargedPositive Ion = CationRemember: Cats have PAWS and are POSITIVEEx: Removing an electron from a K (potassium) atom will….create a POSTITIVE ION = CATIONAnion = When an atom gains an electron, it becomes more negatively chargedNegative Ion = AnionEx: If a Cl (chlorine) atom gains an electron…creates a NEGATIVE ION = ANION
32States of Matter Atoms are in constant motion (called kinetic energy) The rate at which atoms or molecules in a substance move determines its state
33Level of Organization Subatomic particles (p+, e-, n0) atom (O) Element (O)molecule (O2)macromolecules (lipid)Cell (blood cell) <--life begins hereTissue (epithelia tissue)Organ (lung)Organ system (Respiratory System)Organism (Panthera leo (lion))