CHEM 111 Fall 2012: OWLBook Chapter 2

1. CHEM 111 Fall 2012: OWLBook Chapter 2 OWL Assignments Coming Due this Weekend!! Be sure to review units and pre-fixes on your own. This should be material you covered in high school science.

2. X X X X X X X X X X X X X X X X Accuracy and Precision • Accuracy = how close you are to the known value • Precision = how reproducible (similar to each other) your results are

3. Chapter 2: Elements and Compounds • Atomic Structure • Elements and Isotopes • The Periodic Table • Covalent Compounds • Naming • Ions and Ionic Compounds • Naming

4. Atomic Structure • Protons: • Determine the identity of the element • Neutrons • With protons in the nucleus • Stabilize the nucleus (or make it unstable-radioactive) • Result in different isotopes • Electrons • Exist outside of the nucleus • Alter the overall charge on an atom • Adding or subtracting them makes ions

5. Alpha Particle Scattering-helped determine the structure of the atom

7. Subatomic Particles (for CHEM 111)

8. Cathode Ray (electron beam) Tube

9. Mass Spectrometer

11. Atomic Symbols How many protons, neutrons, electrons are in:

13. Isotopes & Atomic Weight • Every form of a unique element is one of its isotopes • Some elements only have one isotope. • Remember-protons are what make an element • Isotopes are forms of an element with different masses • Adding or subtracting neutrons from the nucleus makes isotopes • Some isotopes are stable • Some are unstable • Radioactive

14. Let’s look at some isotopes…

15. Atomic Weight

16. What is the atomic weight of H ?

18. The Periodic Table Groups, Periods, Main Group (A), Lanthanide & Actinide Elements, Metals, Non-Metals, Metaloids (semi-metals), Alkali Metals, Alkaline Earth Metals, Transition Elements (B), Halogens, Noble (“inert”) gases. What is an allotrope?

20. Covalent Compounds • Compounds are formed when two or more elements join in a defined ratio • Covalent compounds consist of elements held together by covalent bonds • Covalent bonds are bonds where electrons are shared between atoms • The atoms don’t have a positive of negative charge on them • Some are named systematically, some have long used “historical” names.

21. Empirical and Molecular Formula • Empirical formula has the ratio of atoms correct, but not necessarily the absolute number of each • HO • CF2 • Molecular formula has the absolute number of each atom in the molecule • H2O2 (hydrogen peroxide) • C2F4 (Teflon monomer)

22. Types of Molecular Models Butanol Wedge and Dash Ball and Stick • C4H10O1 • Formula • Structural Formula

24. Naming Covalent Compounds • Binary, non-metal compounds • Name first element (use prefix if needed) • Name second element, using a prefix if needed • Some have historical names that are more commonly used

25. H2O • CO • CO2 • UF6 • SiO2 • PF5

27. Naming Inorganic Acids (see trends?)(think about other names you may know for these)

29. Ions and Ionic Compounds • Atoms normally have zero net charge • # of electrons = # protons • Ions have gained or lost electrons • Ions can form from any isotope • Ions have nothing to do with the nucleus, only the electrons.

30. Some Monoatomic Ions What do the numbers mean? What is a cation? What is an anion? What trends or patterns do we see? Are these all the monoatomic ions there are?

32. Polyatomic Ions (covalently bonded atoms that carry a charge amongst the whole group)

34. Excuse me, Sir, but how many of these things are we going to have to know? My brain’s turning to Jell-O here!

35. Formulas and Naming Ionic Compounds • Ions can have charge, but ionic compounds should have a net neutral charge • One can have Empirical and Molecular Formulas for ionic compounds • Instead of pre-fixes, IUPAC (International Union of Pure and Applied Chemistry) conventions are used.

36. Naming……. • The name of the cation (+) comes first. • If it has more than one possible charge, that number comes next • The name of the anion comes second. • CaF2 • LiF • Fe2O3 • Formulas • Remember, the charges MUST balance. • Use subscripts to make the charge balance. • Calcium Chloride • Zinc Sulfate • Calcium Nitrate • Magnesium Phosphate