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AP Chemistry
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    • Class
      • Laboratory report rubric
      • Notes
        • 1. Chemical foundations
        • 2. Atoms, molecules, and ions
        • 3. Stoichiometry
        • 4. Types of chemical reactions and solution stoichiometry
        • 5. Gases
        • 6. Thermochemistry
        • 7. Atomic structure and periodicity
        • 8. Bonding: general concepts
        • 9. Covalent bonding: orbitals
        • 10. Liquids and solids
        • 11. Properties of solutions
        • 12. Chemical kinetics
        • 13. Chemical equilibrium
        • 14. Acids and bases
        • 15. Acid-base equilibria
        • 16. Solubility and complex ion equilibria
        • 17. Spontaneity, entropy, free energy
        • 18. Electrochemistry
      • Drug unit
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        • Analgesics
        • Antacids
        • Anesthetics
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    • Textbook (incomplete)
      • 1. Chemical foundations
      • 2. Atoms, molecules, and ions
      • 3. Stoichiometry
      • 4. Types of chemical reactions and solution stoichiometry
      • 5. Gases
      • 6. Thermochemistry
      • 7. Atomic structure and periodicity
      • 8. Bonding: general concepts
    • CED
      • 1. Atomic structure and properties
      • 2. Compound structure and properties
      • 3. Properties of substances and mixtures
      • 4. Chemical reactions
      • 5. Kinetics
      • 6. Thermochemistry
      • 7. Equilibrium
      • 8. Acids and bases
      • 9. Thermodynamics and electrochemistry
AP Chemistry
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2. Atoms, molecules, and ions
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2. Atoms, molecules, and ions

Laws

Law of Conversation of Mass: mass cannot be created or destroyed
Law of Definite Proportions: when two or more atoms combine to make a compound, the ratio is always the same
Law of Multiple Proportions: atoms can combine in different ratios to make different compounds

Atom models

first model of an atom: plum pudding
modern atom:
nucleus
protons (+)
neutrons (x)
electrons (-) surround nucleus

Elements

protons give identity of element
periodic table organizes elements
atomic number: protons
element symbol
average atomic mass (protons + neutrons)
protons = neutrons with neutral charge
ion: atom with charge
charge = protons - electrons
neutrons = atomic mass - atomic number
electrons = protons - charge
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AP Chemistry Atoms.png
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Compounds

Element types

metals (majority of elements): conductive, malleable
nonmetals (mostly on right side): poor conductor, usually gaseous
semi-metals/metalloids: properties of metals and nonmetals

Naming

Ionic compounds

metal + nonmetal
metal: full name
transition metals: use roman numerals to indicate charge
nonmetal
single element: name - suffix + -ide
polyatomic: special names
add elements to neutralize charge
examples
Na + Cl → NaCl → sodium chloride
Ca + F → CaF₂ → calcium fluoride
FeI₃ → ion(III) iodide
Mg(OH)₂ → magnesium hydroxide

Covalent compounds

semi/nonmetal + semi/nonmetal
use prefixes
1: mono-
don’t add this prefix in first element
2: di-
3: tri-
4: tetra-
5: penta-
6: hexa-
7: hepta-
8: octa-
9: nona-
10: deca-
examples
CO → carbon monoxide
CO₂ → carbon dioxide
N₂F₅ → dinitrogen pentafluoride

Laws
Atom models
Elements
Compounds
Element types
Naming
Gallery
 
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