Physical and Chemical Properties of Matter

• Physical properties include state of matter, color, odor, solubility, and electrical conductivity.
• Chemical properties include reactivity with air/water, combustibility, toxicity, and decomposition.

Signs of a Chemical Change

• Production of a new color
• Production of gas bubbles
• Emission of light or heat
• Formation of a precipitate
• Irreversible nature
• Formation of a new substance

Examples of Chemical Changes

• Iron rusting
• Boiling an egg
• Wood burning

Signs of a Physical Change

• Change in state
• Change in shape
• Dissolving of one substance in another
• Often reversible nature
• Affects appearance, not composition

Examples of Physical Changes

• Tearing paper
• Melting ice
• Breaking a bottle

Quantitative Properties

• Viscosity
• Melting point
• Boiling point
• Solubility
• Hardness
• Conductivity
• Density

Qualitative Properties

• Color

• Odor

• State

• Texture

• Lustre

• Malleability

• Matter has mass and volume.

• Matter is broken down into mixtures and pure substances.

Mixtures

• Two or more substances physically combined
• Components retain their identities
• Separable by physical means
• Two types: heterogeneous (mechanical) and homogeneous (solutions)

Heterogeneous Mixtures

• Components are distinguishable
• Examples: granite, salad, mud

Homogeneous Mixtures (Solutions)

• Uniform throughout, no visible separation
• Examples: salt water, air, steel

Pure Substances

• Fixed and definite composition
• Distinct properties
• Two types: elements and compounds

Elements

• Cannot be broken down further
• Only one type of atom
• Atom is the smallest particle

Compounds

• Two or more elements chemically bonded

• Molecule is the smallest particle

• Examples: table salt, pure water, baking soda

• Atoms retain the properties and identities of an element.

• Subatomic particles: protons, neutrons, and electrons

Isotopes

• Version of an element with a different number of neutrons
• Same atomic number, different atomic mass
• Examples: carbon-12 and carbon-14

Radioisotopes

• Unstable isotope that undergoes radioactive decay and gives off radiation

• Example: carbon-14

• Hg and Br are the only elements liquid at room temperature.

• H, O, N, F, Ne, Cl, Ar, Kr, Xe, Rn, and He are gases at room temperature.

• Metals are located on the left and center of the periodic table.

• Metalloids are located in the staircase of the periodic table.

• Non-metals are located on the right of the periodic table.

Groups in the Perodic Table

• Alkali metals: first group (excluding hydrogen)

• Alkaline earth metals: second group

• Halogens: second to last group

• Noble gases: last group

• Atomic radius decreases across a period and increases down a group.

• Ionization energy increases across a period and decreases down a group.

• Electron affinity increases across a period and decreases down a group.

Ions

• Charged particle resulting from an atom gaining or losing electrons

Anions

• Gain electrons
• Negatively charged

Cations

• Lose electrons

• Positively charged

• Metals tend to lose electrons and form ions with the nearest noble gas electron configuration.

• Non-metals tend to gain electrons and form ions with the nearest noble gas electron configuration.

• Electron affinity measures the energy change when an electron is added to form a negative ion.

• Atomic masses are sometimes decimal numbers because they represent an overall value.

• Valence electrons are consistent down a group, energy levels are consistent across a period.

• Electron affinity is the energy released when an atom gains an electron, forming an anion.

• Ionization energy is the energy required to remove an electron from an atom.

Understand the difference between physical and chemical properties of matter. Examine signs and examples of chemical and physical changes. Learn about quantitative and qualitative properties of matter.