Chapter 5, Sec 1Chapter 5, Sec 1

Notes from 10/25/10Notes from 10/25/10

Elements, the Simplest Elements, the Simplest SubstancesSubstances

An An elementelement is a pure substance that cannot be is a pure substance that cannot be separated or broken down into simpler separated or broken down into simpler substances by physical or chemical means. substances by physical or chemical means.

A A pure substancepure substance is a substance in which all is a substance in which all of the “building-block” particles are identical.of the “building-block” particles are identical.

For elements, the building-block particles are For elements, the building-block particles are called called atoms.atoms.

Classifying ElementsClassifying Elements

Each element can be classified by its Each element can be classified by its unique set of characteristic properties.unique set of characteristic properties.

Characteristic propertiesCharacteristic properties include physical include physical properties and chemical properties. properties and chemical properties.

Each element can be identified by its Each element can be identified by its unique set of properties.unique set of properties.

Grouping ElementsGrouping Elements

Elements are classified as metals, nonmetals, Elements are classified as metals, nonmetals, or metalloids based on their properties.or metalloids based on their properties.

MetalsMetals are shiny and conduct heat and electric are shiny and conduct heat and electric current. current. NonmetalsNonmetals are dull in appearance and are dull in appearance and do not conduct heat or electric current.do not conduct heat or electric current.

MetalloidsMetalloids have properties of both metals and have properties of both metals and nonmetals.nonmetals.