Untitled Quiz

Atoms, Molecules, and Ions

• Atoms are extremely small particles making up elements.
• Atoms of the same element have the same size, mass, and chemical properties.
• Atoms of one element are different from atoms of all other elements.
• Compounds are constructed from atoms of more than one element.
• Compounds have a consistent relative number of atoms of each element.
• Chemical reactions involve the rearrangement of atoms.
• Atoms are neither created nor destroyed in chemical reactions.

Dalton's Atomic Theory

• Dalton's Atomic Theory (1808) described the fundamental nature of atoms:
  • Elements are composed of extremely small particles called atoms.
  • All atoms of a given element are identical in size, mass, and chemical properties.
  • Atoms of one element are different from the atoms of all other elements.
  • Compounds are formed when atoms of more than one element combine in a specific ratio.
  • A chemical reaction involves the rearrangement of atoms; atoms are neither created nor destroyed.

Law of Multiple Proportions

• Compounds can have different proportions from the same element.
• This law explains how elements can combine in diverse ratios to form distinct compounds.
• For example, oxygen and carbon can combine in different ratios to form carbon monoxide (CO) and carbon dioxide (CO2).

Law of Conservation of Mass

• The total mass of the reactants in a chemical reaction is equal to the total mass of the products.
• States that matter is not created or destroyed in a chemical reaction.
• Matter is merely rearranged.

J.J. Thomson's Experiment

• Thomson's experiment involved cathode rays and electric fields to discover the electron.
• He found that cathode rays were composed of negatively charged particles.
• This finding contradicted the idea that atoms were indivisible.
• Thomson determined the charge-to-mass ratio of the electron.

Millikan's Experiment

• Millikan's experiment determined the charge of an electron.
• He used oil drops in an electric field to calculate the electron's charge.
• Combined with Thomson's data, this allowed calculation of the mass of an electron.

Radioactivity

• Some substances spontaneously emit radiation composed of different types of particles and energy.
• Three types of rays are alpha (α), beta (β), and gamma (γ) rays.

Rutherford's Gold Foil Experiment

• Rutherford's experiment involved firing alpha particles at a thin gold foil.
• Most particles passed through the foil, but some were deflected or scattered back.
• This suggested that the positive charge of an atom was concentrated in a small, dense nucleus.

The Nuclear Model of the Atom

• The atom consists of a dense, positively charged nucleus.
• Electrons orbit the nucleus in a much larger region of space.
• Atomic radius is much larger than the nuclear radius.

Chadwick's Experiment

• Chadwick's experiment discovered the neutron.
• Neutrons are uncharged particles with a mass similar to that of protons.

Subatomic Particles

• Electron (e⁻): Negative charge, very small mass.
• Proton (p⁺): Positive charge, larger mass than electron.
• Neutron (n⁰): No charge, larger mass than electron.

Atomic Number (Z), Mass Number (A)

• Atomic number (Z): Number of protons in an atom.
• Mass number (A): Number of protons + number of neutrons in an atom.

Isotopes

• Isotopes of an element have the same atomic number (Z) but different mass numbers (A).
• This difference comes from varying numbers of neutrons in the atoms.

The Modern Periodic Table

• Displays elements with similar properties grouped together in columns.
• Organized by atomic number.

Molecules and Molecular Compounds

• A molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical bonds.
• A diatomic molecule consists of two atoms.
• A polyatomic molecule consists of more than two atoms.

Ions and Ionic Compounds

• An ion is an atom or group of atoms that has a positive or negative charge.
• Cations are positively charged ions.
• Anions are negatively charged ions.

Monatomic Ions and Polyatomic Ions

• Monatomic ions are ions containing only one atom.
• Polyatomic ions are groups of atoms that have a charge.

Do You Understand Ions?

• Calculation of protons and electrons in ions is based on the neutral atom's structure.

Formula of Ionic Compounds

• Electrical neutrality must be upheld in ionic compounds.
• Subscripts in a formula indicate the ratio of ions in the compound.

Naming Inorganic Compounds

• Ionic compounds: Metal + nonmetal, and ide suffix.
• Transition metals require Roman numerals for their charge.
• Molecular compounds: Nonmetal + Nonmetal, prefix rules.

Naming Acids

• Acids that contain hydrogen, oxygen, and another element (oxoacids) follow specific naming rules.
• Acids with other functional groups have different naming conventions.

Names and Formulas of Bases

• Bases are substances that release hydroxide ions (OH⁻) in water.
• The naming of bases follow common naming conventions.