States and Properties of Matter

• Effects of the arrangement and motion of atoms and molecules determines the states of matter.

States of Matter

• Solid: Ordered molecular arrangement, does not flow, has a fixed volume, is easily compressed, and diffuses extremely slowly.
• Liquid: Disordered molecular arrangement, flows easily, has a definite volume, is not easily compressed, and has a slow diffusion rate.
• Gas: Very disordered molecular arrangement, flows easily, has no fixed volume, is not easily compressed, and has a fast diffusion rate.

Physical Changes in Matter

• Occur when intermolecular forces are affected.

Phase Changes in Matter

• Sublimation: Solid to gas.
• Melting: Solid to liquid.
• Vaporization: Liquid to gas.
• Condensation: Gas to liquid.
• Freezing: Liquid to solid.
• Deposition: Gas to solid.

Properties of Matter

• Physical Properties: Observed physically about the substance in its natural state.
• Chemical Properties: Observed when chemical changes occur.
• Intensive Properties: Independent of the amount of substance in a material sample and exist at the molecular level. Examples include flammability, density, and boiling point.
• Extensive Properties: Dependent on the amount of substance in a material sample. Examples include mass, surface area, and volume. Density is derived from the ration of mass and volume.

Chemical Properties

• Chemical Change Examples: Indicate that one or more substances form a new substance. Examples include burning wood, rotting fruit, baking a cake, rusting metal, using a battery, digestion, souring milk, exploding fireworks, cooking an egg, and photosynthesis.

Element

• A pure substance made of one type of atom.
• Elements are divided into metals and non-metals.
• Non-metal examples: carbon, oxygen, hydrogen, and nitrogen.
• Metal examples: aluminum, iron, copper, and gold.

Compound

• A substance made up of atoms of two or more different elements joined by chemical bonds.
• Compounds cannot be separated physically.
• Example of a compound: H2O.

History of the Atom: Theories and Models

• John Dalton (1803): Atoms of a particular element differ from other elements.
• J.J. Thomson (1904): Recognized electrons as components of atoms. Plum pudding model that shows the atom as composed of electrons scattered throughout a spherical cloud of positive charge.
• Ernest Rutherford (1911): Realized positive charge was localized in the nucleus of an atom.
• Niels Bohr (1913): Proposed stable electron orbits and explained the emission spectra of some elements.
• Erwin Schrödinger (1926): Electrons do not move around the nucleus in orbits, but in clouds where their position is uncertain.

Parts of an Atom

• Proton: Positive electrical charge.
• Neutron: Neutral charge.
• Electron: Negative electrical charge

Particle Properties

• Electron: Negative charge, mass of 5.486 x 10-24 amu.
• Proton: Positive charge, mass of 1.0073 amu.
• Neutron: Neutral charge, mass of 1.0087 amu.

Mass Number and Atomic Number

• Mass number is the number of protons + number of neutrons.
• Atomic number is the number of protons.

Isotopes

• A variation of an element with the same atomic number but a different mass number.

Isotopes of Hydrogen

• Protium (¹H): 1 proton, 1 electron, 0 neutrons, mass number of 1.
• Deuterium (²H): 1 proton, 1 electron, 1 neutron, mass number of 2.
• Tritium (³H): 1 proton, 1 electron, 2 neutrons, mass number of 3.

Isotopes of Carbon

• Carbon-12: 98.9%, 6 protons, 6 neutrons.
• Carbon-13: 1.1%, 6 protons, 7 neutrons.
• Carbon-14: <0.1%, 6 protons, 8 neutrons.

Uses of Isotopes in Research

• Carbon-14: Carbon dating in archeology and research involved in plant photosynthesis.
• Phosphorus-32 & Phosphorus-33: Research involving biology and genetics.
• Selenium-75: Protein studies in life science.
• Strontium-85: Metabolism and bone formation studies.
• Hydrogen-3 or Tritium: Study life science and drug metabolism.

Electron Configuration

• Describes how electrons are distributed in atomic orbitals.
• Notation: All electron-containing atomic subshells are placed in a sequence.