Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Features of the Periodic Table Periods & GroupsRegions in the Periodic TableSlide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Conceptualizing a MoleConceptualizing a MoleSlide 55Slide 56Slide 57Slide 58Slide 59Slide 60Slide 61Slide 62Slide 63Slide 64Slide 65Slide 66Slide 67Slide 68Slide 69Slide 70Slide 71Slide 72Slide 73Slide 74Slide 75Slide 76Slide 77Slide 78Slide 79Ch 2 Atoms, Molecules, and Ions2.1 Atomic Structure – Protons, Electrons, and NeutronsAtoms are made up of subatomic particles:1. Protons which are positively charged.2. Electrons which are negatively charged.3. Neutrons which are electrically neutral.Chemical properties of elements and molecules depend largely on the electrons in atoms.1Fig. 2-1, p. 5122.2 Atomic Number and Atomic MassAtomic NumberAll atoms of a given element have the same number of protons in the nucleus.Atomic # abbreviated with a ZClicker Q: What is the atomic number of C?3Relative Atomic Mass and the Atomic Mass UnitOne atomic mass unit, 1 u (or amu), is 1/12 of the mass of an atom of carbon with 6 protons and 6 neutrons.Mass numberProtons and neutrons are close to 1 u (electrons are 1/2000 of that), so the number of protons plus neutrons give the mass # of the atom. Symbol for mass number is A.4examples5Clicker Q:How many neutrons does 3169Ga have?27Al3+# of protons?# of neutrons?Clicker Q: # of e 33S2- Clicker Q: # of protons?# of neutrons?# of e 6Table 2-1, p. 5372.3 IsotopesAtoms with the same atomic number but different mass numbers are called isotopes.So have different numbers of neutrons.One example of an isotopic series is the hydrogen isotopes.1H or protium is the most common hydrogen isotope.2H or deuterium is the second most abundant.3H or tritium is a radioactive hydrogen isotope (no known natural sources).89The stable oxygen isotopes provide another example.•16O is the most abundant stable O isotope.•17O is the least abundant stable O isotope•18O is the second most abundant stable O isotope.Clicker Q: Which one is an isotope of 14N?A. 14C B. 16O C. 15N D. 19F E. 3HIsotope AbundancePercentAbundance=number of atoms of an individual isotopetotal number of atoms of all isotopes of that element 10010Determining Atomic Mass and Isotope Abundancehttp://www.chemguide.co.uk/analysis/masspec/howitworks.htmlMass spectrometry (MS) is an analytical technique which identifies compounds based on the atomic sample composition of the molecules and their charge state.http://www.asms.org/about/about-mass-spectrometryA machine used to weigh molecules. A molecular scale.11Table 2-2, p. 562.4 Atomic Weight12Clicker Q: Naturally occurring Cu consists of 2 isotopes. It is 69.1% 63Cu with a mass of 62.9 amu, and 30.9% 65Cu, which has a mass of 64.9 amu. Calculate the atomic weight of Cu to one decimal place.1314Clicker Q: Naturally occurring chromium consists of four isotopes. It is 4.31% 2450Cr, mass = 49.946 amu, 83.76% 2452Cr, mass = 51.941 amu, 9.55% 2453Cr, mass = 52.941 amu, and 2.38% 2454Cr, mass = 53.939 amu. Calculate the atomic weight of chromium.15The atomic weight of boron is 10.811 amu. The masses of the two naturally occurring isotopes 510B and 511B, are 10.013 and 11.009 amu, respectively. Calculate the fraction and percentage of each isotope.The atomic weight of the element is always closer to the mass of the most abundant isotope or isotopes. See the previous boron example. Atomic weight is given in the periodic table162.5 The Periodic TableMost useful tool in chemistry.1869 – Mendeleev (Russian) & Meyer (German)Mendeleev arranged the known elements in order of increasing atomic weight in successive sequences so that elements with similar chemical properties fell into the same column.He provided for elements that were unknown at the time and predicted their properties–Discovered the periodic lawThe properties of the elements are periodic functions of their atomic numbers.17Features of the Periodic TablePeriods & GroupsThe law of chemical periodicity is now stated as the properties of the elements are periodic functions of atomic number.18Regions in the Periodic Table19A brief overview of the periodic table and the chemical elementsGroup 1A is known as the alkali metalsGroup 2A is known as the alkaline earth metals.Group 7A is known as the halogens (salt formers)Group 8A is known as the noble gases (inert or rare gases). Generally lack reactivity.Need to know the names of these groups.20Clicker Q: Na is A. metal B. nonmetal C. metalloidClicker Q: Xe is A. metal B. nonmetal C. metalloidClicker Q: Find the element and input its symbol into clicker that is in period 3 and a halogen.21Fig. 2-9, p. 64Elements that exist as diatomic/triatomic molecules. Have to know these.22Allotropes: an element can often exist in several different and distinct forms each having its own properties. Carbon is an example:232.6 Molecules, Compounds, and FormulasA molecule is the smallest identifiable unit into which some pure substances like sugar and water can be divided and till retain the composition and chemical properties of the substance. 2H2 + O2 → 2H2O24FormulasMolecular formula describes the composition of the compound. Tells you how many atoms of each are present.25Molecular ModelsSeveral different ways of representing compounds/molecules.26p. 69Clicker Q: What is molecular formula of the above molecule? Remember to put in ABC order.Gray: carbonWhite: hydrogenRed: oxygenBlue: nitrogenYellow: sulfur272.7 Ionic Compounds: Formulas, Names, and PropertiesMolecular compounds: compounds that consist of discrete molecules at the particulate level. Naming done by “prefix system”Ionic compounds: consist of ions, atoms, or groups of atoms that bear a positive or negative electric charge. Naming: metal then nonmetal28IonsHave an electric charge. So either lost or gained electrons. There is 2 kinds: Cations (+ ions) and anions (- ions).CationsAre positive ions. Lost one or more electrons (remember e are negative), so then has more protons and is thus positive.AnionsAre negative ions. Gained one or more electrons.29Fig. 2-17, p. 7030Monatomic