Final Study Guide: Part 1 Chem. Mr. Malveaux Refer to your class notes, worksheets, and the textbook to complete this review sheet. Study early so that you will have time to ask questions about what you don’t understand. (* The study of matter and the changes it undergoes) Matter: Anything that takes up space and has mass Physical Changes and Chemical Changes Define each. How can you tell the difference between the two? Classify the following as physical or chemical changes: a. spoiling of milk ___________________ b. bending wire _____________________ c. cutting paper _____________________ d. rusting of a nail ___________________ Put the following into a graphic organizer/flowchart and define each: Matter Pure substances – elements and compounds Mixtures – homogeneous (solutions) and heterogeneous Identify the following as pure substances, homogeneous mixtures or heterogeneous mixtures: a. copper ______________________ b. sweetened tea ________________ c. sand and water _______________ d. calcium carbonate (CaCO3) ________________________ Sketch particles in the three states of matter. How close are the particles and how much do they move? Solid Liquid Calculations using the Law of Conservation of Mass for Reactions 4g H2 + ?? g O2 → 36g H2O Atom For this Carbon–14 isotope, 146 C Atomic number = _____, Mass number = _____, Gas # of protons = _____, # of electrons = _____, # of neutrons = _____. Atomic Masses: What is the difference between the mass number for Carbon–14 and carbon’s atomic mass of 12.011 amu? Calculate the atomic mass of lithium is one isotope has a mass of 6.0151 amu and a percent abundance of 7.59% and a second isotope has a mass of 7.0600 amu and a percent abundance of 92.41%. Atomic Models: Philosophers: Democritus (believed in atoms) and Aristotle (didn’t believe in atoms) Scientists: What was the contribution of each one’s atomic model? Draw a model of each. John Dalton List the four postulates of Dalton’s Atomic Theory: J.J. Thompson Earnest Rutherford Niels Bohr Quantum mechanical model (Werner Heisenberg): Energy levels (n=1, 2, 3, 4,…) – represented by periods on the periodic table Sublevels: (s, p, d, f) – represented by blocks on the periodic table Orbitals – region of space where up to 2 electrons may be found Electron Configurations. What element has the configuration [Ne]3s23p1? _____ What does the 3 mean in 3s2 ? What does the s mean? What does the 2 mean? How many valence electrons will an atom of this element have? How many electrons will an atom of this element lose to form an ion? Why? Write out the electron distribution according to Hund’s rule. The 1s2 sublevel is done for you. 1s2_↑ ↓___ 2s2 ____ 2p6 ____ ____ ____ 3s2 ____ 3p6 ____ ____ ____ Emission (or bright-line) Spectrums What is needed for an electron to “jump” to a higher energy level? What happens when an “excited” electron falls back to its ground state? What does an emission spectrum (radio – gamma) allow one to do? Characteristics of subatomic particles Particle Proton Neutron Electron Periodic trends Mass Charge Location in atom Locate or define parts of the periodic table: Groups Periods Transition metals (d & f blocks) vs. Representative Elements (s & p blocks) Alkali metals, Alkaline Earth metals, Halogens, Noble Gases Periodic Trends: Increasing or Decreasing from top to bottom or left to right? Top to Bottom in a Group Left to Right across a Period electronegativity ionization energy atomic size Elements in the same ___________ have similar physical and chemical characteristics because the (group, period) they have the same number of _____________________. (atoms, protons, neutrons, electrons, valence electrons) Draw a electron dot diagram (or Lewis Dot structure) for Be and for N correct number of valence electrons showing the From their positions on the periodic table, what charges would the ions of Be and N have? Gains or loses electrons? Be Symbol for ion Gains or loses electrons? Symbol for ion N Properties of Metals vs. Nonmetals vs. Metalloids Metals Luster? Malleable vs. Brittle Conducts electricity & heat? Typical state(s) at room temperature Nonmetals Metalloids Ionic vs. Molecular Compounds: Ionic bonds are formed when a ____________ and a _________________ combine. Metals lose electrons and form _____________ while nonmetals gain and electrons form __________. Molecular compounds form when a ______________ and a _______________ combine as they share electrons. Identify the following pairs of atoms as potentially forming an ionic or molecular compound: Mg and Cl ____________ I and F _________________ P and Cl _______________ Ag and S _____________ K and Br ________________ Sn and O _______________ Covalent Bonding in Molecules Draw Lewis Structures (dot diagrams) for HCl, H2S, CH2Cl2, and O3. Use Lewis Structures to predict molecular shapes and polarity of molecules Identify shapes of the molecules as: Linear, Bent, Pyramidal, Trigonal Planar, or Tetrahedral. Use electronegativity values to determine if the individual bonds in the molecules above are polar. Look at the polarity of the bonds and the symmetry of the molecules above to determine if the molecules are polar (if one side of the molecule will be more negative than another). H He Electronegativity Type of Bond 2.1 Difference (x) Li Be B C N O F Ne Non–polar 0.0 x 0.4 1.0 1.5 2.0 2.5 3.0 3.5 4.0 covalent Na Mg Al Si P S Cl Ar 0.4 < x < 2.0 Polar covalent 0.9 1.2 1.5 1.8 2.1 2.5 3.0 K Ca Ga Ge As Se Br Kr Ionic 2.0 x 0.8 1.0 1.6 1.8 2.0 2.4 2.8 N2 Lewis Structures & Total # of Valence Electrons Structural Formula Shape of Molecule Bond Angle Hybridization HCl H2S CH2Cl2 O3 Properties of Ionic and Molecular Compounds Molecular Compounds Ionic Compounds Combination of elements involved (metals? nonmetals?) How is bond formed? Typical state(s) at room temperature Melting and boiling points (relatively high or low?) Conduct electricity if dissolved in water? Naming Molecular and Ionic Compounds Naming molecular compounds Name: N2O: ___________________________ and NO2 ____________________________ Naming Ionic Compounds Name: Li2O ___________________________ and (NH4)2SO4 __________________________ Name: FeO __________________________ and Sn3(PO4)4 ___________________________ Name: NaHCO3 ______________________ and CuCl2 _______________________________ Formulas of Molecular and Ionic Compounds Write formulas for the following molecular compounds: Water _____________________________________ silicon dioxide _________________________ Phosphorous trihydride _______________________ dioxygen difluoride _____________________ Lead (II) hydroxide __________________________ chromium (III) sulfate ___________________ Write formulas for: _________________ Ba2+ with OH– ___________ iron (III) sulfide Na+ with OH– ___________ NH4+ with PO43– ______________ magnesium oxide____________