Chemistry Laws and Molecules Quiz

Laws of Chemical Combination

• The law of definite proportions does not apply consistently when isotopes of elements are used in a compound.
• Dalton's atomic theory explained existing laws of chemical combination. He assumed the simplest compound of two elements is binary.

Atoms, Molecules, Ions & Chemical Formulas

• Atom: The smallest particle of an element that can participate in a chemical reaction. May or may not exist independently. Each atom possesses the properties of the element.
• Molecule: The smallest particle of matter (element or compound) that can exist independently. A substance's properties are the same as its molecules' properties.
  • Element Molecules: Composed of the same type of atoms.
  • Compound Molecules: Formed when atoms of different elements combine in definite proportions (heteratomic molecules).
• Atomicty: The number of atoms in a molecule of a substance (element or compound).
• Elements:
  • Ozone (O₃): Atomicty - 3
  • Phosphorus (P₄): Atomicty - 4
  • Sulfur (S₈): Atomicty - 8
  • Oxygen (O₂): Atomicty - 2
• Types of Molecules Based on Atomicty:
  • Monoatomic: Noble gases (e.g., Helium (He), Neon (Ne), Argon (Ar))
  • Diatomic:
  • Triatomic:

Symbols

• Element symbols are usually the first letter of the English name in capital.
• If multiple elements start with the same letter, the second letter is used in the symbol.
• Some symbols are derived from Latin names.
  • Sodium (Na) / Natrium:
  • Copper (Cu) / Cuprum:
  • Potassium (K) / Kalium:
  • Iron (Fe) / Ferrum:
  • Mercury (Hg) / Hydragyrum:
  • Tungsten (W) / Wolfram:

Polyatomic Ions

• A group of atoms with a net charge.

Valency

• The combining capacity of an atom. This is the number of electrons an atom can lose, gain, or share to form a bond.

Chemical Formulas

• A concise way to represent elements and compounds.
• Chemical formulas follow certain rules (e.g., the criss-cross rule)

Test your knowledge on the laws of chemical combination and the definitions of atoms, molecules, and ions. This quiz covers Dalton's atomic theory and the characteristics of different types of molecules. Understand the basics that define chemical reactions and matter.