Chapter 4 - Elements, Mixtures and Compounds Section 1 – Elements (pp. 90-93)

ELEMENT Definition: An element is a pure substance that cannot be separated into simpler substances by physical or chemical means Grinding -heating Electrolysis -filtering

PURE SUBSTANCE Definition of a pure substance: A pure substance is a substance in which there is only one type of particle Because elements are pure substances, each element only contains one type of particle

PURE SUBSTANCE The particles of a pure substance are alike no matter where the substance is found Example: an iron skillet and a meteorite have the same type of particle (iron) in them

ELEMENTS Have characteristic properties that do not depend on the amount of material that is present in the sample Elements are classified by their properties. They are grouped into categories according to their shared properties. If you know the category, you know the element.

3 CATEGORIES OF ELEMENTS

METALS Are shiny Are good conductors of thermal energy Are good conductors of electric current Are malleable Are ductile

METALS Examples: Copper Lead Aluminum

NONMETALS Are not shiny (are dull) Are poor conductors of thermal energy Are poor conductors of electric current Solids are brittle Solids are not malleable

NONMETALS neon graphite sulfur bromine

METALLOIDS Have properties of both metals and nonmetals Some are shiny, some are dull Are somewhat malleable and ductile Some conduct thermal energy and electric current well, others do not

METALLOIDS Examples: antimony silicon boron