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Properties of Matter & Identifying Substances
Compound – when two or more elements combine chemically.
Mixture–when two or more substances are combined but do not join together.
Period – the horizontal rows on the periodic table. Periods are numbered 1 to 7. The elements in periods are arranged in order of increasing atomic number.
Group or “Family” – the vertical columns on the periodic table. Groups or Families are numbered 1 to 18 (as well as from 1A to 8A). Elements in the same group or family have similar chemical properties. The elements in a group all share the same number of valance electrons.
NOTE: Elements in groups 1-2 and 13-18 are the main group elements. Elements in groups 3-12 are called transition elements.
Reactivity – describes how likely an element is to form bonds with other elements.
Physical Property – a characteristic of a substance that can be observed without changing the identity of the substance.
Chemical Property – a characteristic that describes how the matter will change under certain conditions causing the substance to change it’s identity.
Metal – an element that is a good conductor of electricity and heat.
Nonmetal – an element that DOES NOT readily conduct electricity or heat.
Metalloid – an element that has properties of both metals and nonmetals.
Inert – elements that are unable to react chemically.
Malleable – able to be hammered and shaped or rolled into thin sheets.
Ductile – able to be stretched or drawn into wires without breaking.
Magnetism – a force of attraction or repulsion that exists.
Conductor – a material or substance that allows electrons to flow through it easily.
Insulator – materials or substances that DO NOT allow electricity to flow through them easily.
Semiconductor – materials or substances that has properties of both conductors and insulators.
Density – D=M/V, the ratio of mass to volume.
Solubility – a measure of how much of a substance dissolves in a given amount of another substance.(Ex: The measurement of how much salt dissolved in 1 cup of water)
Soluble – able to dissolve.(Ex: Water is soluble, it is able to dissolve)
Solute – the substance dissolved in a given solution.(Ex: Kool-Aid powder is a solute)
Solvent – a substance in which another substance dissolves.(Ex: Water dissolves other substances. Water is the “Universal Solvent.”)
Solution – a mixture in which the particles are too small to be distinguished from each other and remain constantly and uniformly mixed.(Ex: Kool-Aid powder, water and sugar when prepared together remain constantly and uniformly mixed.)
Melting Point – the temperature at which a solid changes to a liquid.
Boiling Point – the temperature at which gas bubbles form in a liquid and rise to the surface to escape the liquid as a gas.
Specific Heat – the amount of heat needed to raise 1 gram (1g) of a substance by 1 degree Celsius (1˚C).
The unit of measurement is J/g˚C.