• Matter is defined by its properties, characteristics, and behavior.
• Properties of matter are either Chemical, Physical, Intensive, or Extensive.

Chemical Properties

• Chemical properties define a substance's ability or inability to change into a new substance, relating to a chemical change or reaction.
• Examples include:
• Reactivity - how a substance reacts.
• Instability - a substance's tendency to break down.
• Toxicity - how poisonous/toxic a substance is.
• pH - how acidic or basic a substance is.
• Flammability - the ease with which a substance burns.
• Melting point - temperature where a substance melts.

Physical Properties

• Physical properties are characteristics that can be measured or observed without changing the composition of the substance..
• Examples include:
• Mass - amount of matter (constant).
• Weight - measure of gravitational force.
• Volume - amount of space occupied.
• Color - ROYGBIV
• Texture - how it feels.
• Hardness - quality of being hard (firm or solid).
• Malleability - ability to be hammered.
• Elasticity - ability to return to original position after stretching.
• Ductility - ability to be drawn into a wire.
• Conductivity - ability to transfer heat, electricity, or sound.
• Solubility - capacity to be dissolved.
• Boiling point - vapor pressure equals external pressure.
• Freezing point - liquid solidifies.
• Density - mass per volume unit.

Intensive vs. Extensive Properties

• Intensive properties do not change with the amount of substance and can be used for identification.
• Extensive properties constantly change and cannot be used for identification.

Matter, Atoms, and Molecules

• Matter takes up space, has mass, and is made of atoms.
• Atoms are the building blocks of matter and are too small to be seen (Angstrom = unit of length equal to one ten millionth of a millimeter).
• Molecules consist of two or more atoms combined in a certain arrangement.

States of Matter

• Gas particles move randomly and quickly in a straight line, taking the shape of their container.
• Liquid particles move and change locations but not as freely as gas.
• Solid particles are held together, have definite shapes and volume.

Phase Changes

• Evaporation is the change from liquid to gas (cooling process).
• Condensation is the change from gas to liquid.
• Melting is the change from solid to liquid.
• Freezing is the change from liquid to solid.
• Sublimation is the change from solid to gas.
• Deposition is the change from gas to solid.

Atoms and Subatomic Particles

• Atoms are electrically neutral but carry electrically charged particles.
• Protons are positive.
• Electrons are negative.
• Neutrons are neutral.
• Protons are positive, electrons are negative and lightest, and neutrons are neutral and heaviest.
• Democritus and Leucippus believed that nature consists of atoms and the void; atomos means indivisible particle.
• Democritus- believed that atoms were uniform, solid, hard, incompressible, and indestructible, but Aristotle rejected this idea.
• John Dalton (1803) envisioned atoms as solid, hard spheres, and used wooden balls to model them (Solid sphere/billiard ball/bowling ball model).
• JJ Thomson (1904) discovered the electron (Plum pudding model).
• Ernest Rutherford (1911) discovered the proton during the Alpha Particle Scattering Experiment (Nuclear model).
• Niels Bohr (1913) proposed that electrons encircle the nucleus in specific paths called orbits (Planetary/Bohr model).
• Erwin Schrodinger (1926) used mathematical equations to describe the likelihood of finding an electron in a certain position (Quantum mechanical model).
• James Chadwick discovered the neutron.

Periodic Table Arrangement

• Elements in the periodic table are arranged based on atomic number, electronic configuration, and recurring chemical properties.
• Atomic # = # of protons

• of protons = # of electrons (in neutral atoms)

• Charge = # of protons - # of electrons
• Positive charge - minus.
• Negative charge - add

Isotopes and Atomic Mass

• Isotopes are atoms of the same element with the same number of protons but a different number of neutrons.
• Mass # distinguishes isotopes of a particular element.
• Mass #= # of protons + # of neutrons

• of neutron = mass # - atomic # (# of proton)

• Mass Number is the sum of the # of protons and neutrons
• Atomic mass/atomic weight is the weighted average mass of an atom.

History of the Periodic Table

• Johann Wolfgang Dobereiner (1829) identified groups of 3 elements with similar properties (triads).
• John Newlands (1863) arranged the periodic table by increasing order of atomic masses and noted that every 8th element had similar properties (Law of Octaves).
• Dmitri Mendeleev (1869) created the framework of the periodic table believing that atomic mass was most fundamental.
• Mendeleev's Law - Physical and chemical properties are periodic functions of atomic masses.
• Henry Moseley (1913) determined that the atomic number is the most fundamental property.
• Modern Periodic Law - the chemical and physical properties are periodic functions of their atomic number.

Periodic Table Trends

• Period - horizontal row (1-7)
• Groups/Families - vertical columns (1-18)
• Atomic Radius decreases from left to right and increases from top to bottom.
• Ionic Radius decreases from left to right and increases from top to bottom.
• Ionization Energy increases from left to right and decreases from top to bottom.
• Electron Affinity increases from left to right and decreases from top to bottom.
• Electronegativity increases from left to right.
• Metallic Property how easy it is for an atom to lose electrons.
• Nonmetallic Property how easy it is for an atom to gain an electron
• Metallic Character decreases from left to right and increases from top to bottom.
• Nonmetallic Character increases from left to right and decreases from top to bottom.
• Reactivity of a Metal is the ability to ionize or share electrons.
• More reactive metals gain/lose electrons.
• Less reactive metals share electrons.
• A more reactive metal can replace a less reactive metal; a less reactive metal cannot replace a more reactive metal.

Explore the defining characteristics of matter, including chemical and physical properties. Learn about reactivity, flammability, mass, volume, and other key properties that describe matter's behavior and composition. Understand intensive and extensive properties.