Chapter 4 Elements Compounds and Mixtures Section 1 Elements

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.

Elements are Grouped into 3 Categories Metals ( Copper) Nonmetals (neon) Metalloids (silicon)

Properties of Metals Shiny Conduct electric current Conduct heat energy Examples: tin,copper, iron, lead

Properties of Nonmetals Dull Poor conductors of electricity Poor conductors of thermal energy Brittle Not malleable Example: neon, iodine, sulfur

Metalloids(Semi Conductors) Have properties of both metals and nonmetals Some shiny some dull Somewhat malleable and ductile Some conduct thermal energy and electric current well Example: silicon, boron and antimony

Characteristic Properties Physical: such as melting point, boiling point, density, texture, color Chemical: such as reactivity with acid or oxygen and flammability Electrolysis to separate water