The Chemist’s Shorthand: Atomic Symbols

1. The Chemist’s Shorthand: Atomic Symbols • Element Symbols • Neon • Ne • Chlorine • Cl • Nitrogen • N

2. The Chemist’s Shorthand: Atomic Symbols • Oxygen • O • Silicon • Si • Zinc • Zn

3. The Chemist’s Shorthand: Atomic Symbols • Gold • Au • Lead • Pb • Sodium • Na • Iron • Fe

4. The Chemists’ Shorthand:Formulas • Chemical Formula: • Symbols = types of atoms • Subscripts = relative numbers of atoms • CO2 • Structural Formula: • Individual bonds are shown by lines. • O=C=O

5. The Chemists’ Shorthand:Formulas • A molecule contains four phosphorus atoms and ten oxygen atoms. • P4O10 • A molecule contains one aluminum atom and three chlorine atoms. • AlCl3

6. The Mass and Change of the Electron, Proton, and Neutron

7. The Chemists’ Shorthand: Atomic Symbols 39 Mass number  K  Element Symbol 19 Atomic number 

8. Isotopes • Atoms with the same number of protons but different numbers of neutrons. • K-39 and K-40 • Na-23 and Na-24 • H-1, H-2, and H-3

9. Periodic Table • Elements classified by: • -properties • -atomic number • Groups (vertical) • 1A = alkali metals • 2A = alkaline earth metals • 7A = halogens • 8A = noble gases • Periods (horizontal)

10. Periodic Table • Transition metals • Metals • Nonmetals • Semimetals (Metalloids)

11. Ions • Cation: A positive ion • Mg2+, NH4+ • Anion: A negative ion • Cl, SO42

12. Ions • Mg2+ • # of protons and electrons • 12 protons and 10 electron • Mg -> Mg2+ + 2e- • Lost 2 electrons

13. Ions • K+ • # of protons and electrons • 19 protons and 18 electron • K -> K+ + e- • Lost 1 electron

14. Ions • Cl • # of protons and electrons • 17 protons and 18 electron • Cl + e- -> Cl- • Gained 1 electron

15. Ions • O2- • # of protons and electrons • 8 protons and 10 electron • O + 2e- -> O2- • Gained 2 electrons

16. Writing Formulas for Ionic Compounds • 1. Na+ and S2- • Na2S • 2. Ca2+ and P3- • Ca3P2 Ionic Compounds: Net Charge of Zero

17. Naming Compounds Binary Ionic Compounds: • 1. Cation first, then anion • 2. Monatomic cation = name of the element • Ca2+ = calciumion • 3. Monatomic anion = root + -ide • Cl = chloride • CaCl2 = calcium chloride

18. Naming Compounds Binary Ionic Compounds: • NaCl • sodium chloride • AlF3 • aluminum fluoride • MgBr2 • magnesium bromide

19. Naming Compounds • - When metal forms more than one cation • - use Roman numeral in name • PbCl2 • Pb2+is cation • PbCl2 = lead (II) chloride Binary Ionic Compounds:

20. Naming Compounds • CuCl • copper(I) chloride • CuBr2 • Copper(II) bromide • FeF3 • iron(III) fluoride Binary Ionic Compounds:

21. Naming Compounds • - Compounds between two nonmetals • -Second element is named as if it were an anion. • - Use prefixes • - Never use mono- for the first element. • P2O5 = diphosphorus pentoxide Binary molecular compounds:

22. Naming Compounds • P2O5 • diphosphorus pentoxide • CCl4 • carbon tetrachloride Binary compounds:

23. Naming Compounds Binary compounds: • N2O3 • dinitrogen trioxide • SCl6 • sulfur hexachloride

24. Polyatomic Ions to Memorize • NO3– • Nitrate ion • NO2- • Nitrite ion

25. Polyatomic Ions to Memorize • SO42- • Sulfate ion • SO32- • Sulfite ion

26. Polyatomic Ions to Memorize • CO32- • Carbonate ion • HCO3- • bicarbonate or hydrogen carbonate ion

27. Polyatomic Ions to Memorize • PO43- • Phosphate ion

28. Polyatomic Ions to Memorize • NH4+ • Ammonium ion

29. Compounds with Polyatomic Ions • K2SO4 • potassium sulfate • NaNO3 • sodium nitrate

30. Compounds with Polyatomic Ions • K2CO3 • potassium carbonate • Na3PO4 • sodium phosphate

31. Writing Formulas from Names • Disulfur dichloride • S2Cl2 • Potassium oxide • K2O • calcium phosphate • Ca3(PO4)2

32. The Mole • The number equal to the number of carbon atoms in exactly 12 grams of pure 12C. • 1 mole of anything = 6.022  1023units of that thing

33. Avogadro’s number equals6.022  1023 units

34. Molar Mass • A substance’s molar mass(molecular weight) is the mass in grams of one mole of the compound. • CO2 = 12.0107 + 2 x 15.9994 • = 44.0095 grams per mole

35. Molar Mass • How many moles of CaCl2 are in a 10.0 g-sample of CaCl2? The molar mass of CaCl2 is 110.98 g/mole. • Moles = mass x (1/molar mass) • = 10.0 g x (1 mole / 110.98 g) • = 0.090106 • = 0.0901 mole (3 sig figs)

36. Molarity (M) • concentration expressed as moles of solute per liter of solution. • M = moles of solute/L of solution • Moles of solute = Molarity (M) x L of solution • L of solution = moles of solute/Molarity (M)

37. Molarity (M) • Calculate the molarity of a solution prepared by dissolving 65.5 g of solid NaCl in enough water to make 4.50 L of solution. • M = moles of solute/L of solution • Moles of NaCl = mass x (1/molar mass) • Molar mass of NaCl = 22.989770 + 35.453 = 58.443 g/mole • Moles of NaCl = 65.5 g x (1 mole/58.443 g ) • = 1.12075 moles • Molarity = 1.12075 moles/4.50 L = 0.249 M

38. Chemical Equations • Chemical change involves a reorganization of the atoms in one or more substances.

39. Chemical Equation • A representation of a chemical reaction: • C2H5OH (l) + O2 (g)  CO2(g) + H2O(g) • C2H5OH (l) +3O2 (g) 2CO2(g) +3H2O(g) • reactants products

40. To Balance a Chemical Equation • Start with the most complicated molecule. • Use the smallest integers for the coefficients. • Never change the chemical formula (subscripts)

41. Balance the following Chemical Equation • Li(s) + Cl2 (g) -> LiCl(s) • 2Li(s) + Cl2 (g) -> 2LiCl(s)

42. Balance the following Chemical Equation • Ca(s) + HCl (aq) -> CaCl2 (aq) + H2(g) • Ca(s) + 2HCl (aq) -> CaCl2 (aq) + H2(g)

43. Balance the following Chemical Equation • C12H22O11(s) + __O2(g) -> __CO2(g) + __H2O(g) • C12H22O11(s) + 12O2(g) -> 12CO2(g) + 11H2O(g)