Chemistry Lecture Notes

Introduction to Chemistry

• Focus: Periodic Table and basic chemistry concepts
• Important for students about to begin chemistry courses.

Periodic Table Overview

Group 1 (Alkali Metals)

• Elements:
  • H (Hydrogen)
  • Li (Lithium)
  • Na (Sodium)
  • K (Potassium)
  • Rb (Rubidium)
  • Cs (Cesium)
• Ions: Typically form +1 charge.

Group 2 (Alkaline Earth Metals)

• Elements:
  • Be (Beryllium)
  • Mg (Magnesium)
  • Ca (Calcium)
  • Sr (Strontium)
  • Ba (Barium)
• Ions: Typically form +2 charge.

Group 13 (3A)

• Elements:
  • B (Boron)
  • Al (Aluminum)
  • Ga (Gallium)
  • In (Indium)
  • Tl (Thallium)
• Ions: Can form +3 charge.

Group 14

• Elements:
  • C (Carbon)
  • Si (Silicon)
  • Ge (Germanium)
  • Sn (Tin)
  • Pb (Lead)
• Ions: Can form +2 or +4 charge.

Group 15 (5A)

• Elements:
  • N (Nitrogen)
  • P (Phosphorus)
  • As (Arsenic)
  • Sb (Antimony)
  • Bi (Bismuth)
• Ions: Typically form -3 charge.

Group 16 (6A - Chalcogens)

• Elements:
  • O (Oxygen)
  • S (Sulfur)
  • Se (Selenium)
  • Te (Tellurium)
  • Po (Polonium)
• Ions: Typically form -2 charge.

Group 17 (7A - Halogens)

• Elements:
  • F (Fluorine)
  • Cl (Chlorine)
  • Br (Bromine)
  • I (Iodine)
• Ions: Typically form -1 charge.

Group 18 (8A - Noble Gases)

• Elements:
  • He (Helium)
  • Ne (Neon)
  • Ar (Argon)
  • Kr (Krypton)
  • Xe (Xenon)
• Characteristics: Chemically inert and stable.

Transition Metals (Groups 3-12)

• Notable Elements:
  • Ti (Titanium), Cr (Chromium),
  • Mn (Manganese), Fe (Iron),
  • Co (Cobalt), Ni (Nickel),
  • Cu (Copper), Zn (Zinc),
  • Ag (Silver), Cd (Cadmium),
  • Hg (Mercury), Au (Gold), Pt (Platinum).

Inner Transition Metals

• Lanthanide and Actinide series, notable elements:
  • Th (Thorium), U (Uranium).

Distinguishing Atoms and Molecules

Atoms vs. Molecules

• Atoms: Single elements (e.g., Zinc, Iron, Aluminum).
• Molecules: Composed of multiple atoms (e.g., H2, O2, Cl2).

Elements vs. Compounds

• Element: Consists of one type of atom (e.g., Zn, H).
• Compound: Consists of different types of atoms (e.g., NaCl, H2O).

Types of Compounds

• Ionic Compounds: Composed of metals and nonmetals (e.g., NaCl).
• Molecular Compounds: Composed of nonmetals (e.g., CO2).

Metals, Nonmetals, and Metalloids

• Use the periodic table to distinguish:
  • Metals: Left of the metalloid line, give away electrons.
  • Nonmetals: Right of the metalloid line, acquire electrons.
  • Metalloids: Properties of both categories.

Naming Compounds

Molecular Compounds

• Named using prefixes (e.g., CO2 = Carbon Dioxide).
• Common prefixes:
  • Mono- (1), Di- (2), Tri- (3), Tetra- (4), Penta- (5), Hexa- (6), Hepta- (7), Octa- (8), Nona- (9), Deca- (10).

Ionic Compounds

• Simple naming (e.g., KI = Potassium Iodide).
• Use Roman numerals for transition metals to indicate charge (e.g., FeCl2 = Iron(II) Chloride).

Polyatomic Ions

• Common examples:
  • SO4^2- (Sulfate), OH^- (Hydroxide), NH4^+ (Ammonium), NO3^- (Nitrate).

Isotopes

• Definition: Atoms with the same number of protons but different numbers of neutrons.
• Example: Carbon-12 (6 protons, 6 neutrons) vs. Carbon-13 (6 protons, 7 neutrons).

Calculating Protons, Neutrons, and Electrons

• Protons = Atomic Number
• Neutrons = Mass Number - Atomic Number
• Electrons = Atomic Number (for neutral atoms) or Atomic Number - Charge (for ions).

Practice Calculation

• Nitrogen-15: 7 protons, 8 neutrons, 7 electrons.
• Aluminum-27 with +3 charge: 13 protons, 14 neutrons, 10 electrons.
• Sulfur-34 with -2 charge: 16 protons, 18 neutrons, 18 electrons.