Chemistry Basics Lecture Notes

Introduction

• Focus on fundamental chemistry topics for upcoming courses.

Periodic Table Overview

Elements and Groups

• Group 1A (Alkali Metals): Hydrogen (H), Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs)
  • Most reactive metals
  • React violently with water (e.g., Sodium)
  • One valence electron -> forms +1 cations.
• Group 2A (Alkaline Earth Metals): Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba)
  • Reactive, less so than alkali metals
  • Two valence electrons -> forms +2 cations.

Transition Metals

• Located between groups 1A and 2A
• Include: Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn)
• Variable oxidation states (e.g., Fe can be +2 or +3).

Representative Elements (Groups 13-18)

• Group 3A (13): Boron (B), Aluminum (Al), Gallium (Ga), Indium (In), Thallium (Tl)
  • Three valence electrons -> +3 cations (mostly Al).
• Group 4A (14): Carbon (C), Silicon (Si), Germanium (Ge), Tin (Sn), Lead (Pb)
  • Four valence electrons -> can form +2 or +4 cations.
• Group 5A (15): Nitrogen (N), Phosphorus (P), Arsenic (As), Antimony (Sb), Bismuth (Bi)
  • Five valence electrons -> typically forms -3 anions (e.g., Nitride, Phosphide).
• Group 6A (16): Oxygen (O), Sulfur (S), Selenium (Se), Tellurium (Te), Polonium (Po)
  • Six valence electrons -> forms -2 anions (e.g., Oxide, Sulfide).
• Group 7A (17): Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At)
  • Seven valence electrons -> forms -1 anions (e.g., Fluoride, Chloride).

Noble Gases (Group 18)

• Chemically inert and stable (e.g., Helium, Neon, Argon).

Metals vs Non-Metals

• Metals: Generally found on the left side of the periodic table, good conductors, malleable, ductile.
• Non-Metals: Found on the right side of the periodic table, poor conductors, tend to gain electrons.
• Metalloids: Elements that exhibit properties of both metals and non-metals (e.g., Silicon, Germanium).

Bonds

Ionic Bonds

• Formed between metals and non-metals through the transfer of electrons.
• Characterized by formation of cations and anions (e.g., NaCl).

Covalent Bonds

• Formed when two non-metals share electrons.
• Can be polar (unequal sharing, e.g., HF) or non-polar (equal sharing, e.g., H2).

Atomic Structure

• Atomic number = number of protons.
• Average atomic mass = weighted average of isotopes.

Isotopes

• Same element with different numbers of neutrons (e.g., Carbon-12, Carbon-14).
• Average atomic mass may not be a whole number due to isotopic abundance.

Significant Figures

• Rules for counting significant figures in numbers and for rounding during calculations.

Naming Compounds

Ionic Compounds

• Use the name of the metal and the name of the non-metal with an '-ide' suffix (e.g., NaCl = Sodium Chloride).

Molecular Compounds

• Use prefixes for the number of atoms (e.g., CO2 = Carbon Dioxide).

Reaction Types

Combustion

• Hydrocarbon + O2 → CO2 + H2O.

Redox Reactions

• Involves transfer of electrons; oxidation state changes.

Balancing Reactions

• Ensure the number of each type of atom is the same on both sides (adjust coefficients as necessary).

Conclusion

• Review key concepts for upcoming exams and labs.
• Additional resources include videos on stoichiometry, molarity, etc.