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Characteristics of Substances. Elements, compounds, mixtures. Atoms. Smallest piece. Elements. Red block. Blue block. Each type of Atom is called an Element. Elements are substances made up of only one type of atom. Example:.
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Characteristics of Substances Elements, compounds, mixtures
Atoms Smallest piece
Elements Red block Blue block Each type of Atom is called an Element
Elements are substances made up of only one type of atom. • Example:
MoleculesA molecule is made up of two or more atoms chemically combined. O H H Water (H2O)
Chemical Reaction Element or Molecules combining together = > Chemical Reaction O O H + H H H Water (H2O)
Aristotle's Elements Earth Air Fire Water
What is an Element ? • Everything in the Universe is made from Elements • There are over 100 elements • The most common element in the Universe is Hydrogen • The Term “Element” was introduced by an Irish scientist Robert Boyle – • “Simple Substance”
Element An Element is a substance that cannot be split up into simpler substances by chemical means.
Symbols • Each Element is given a unique Symbol • First letter of its name (H, C, O) • First two letters of its name (Si, Ne, Li) • Taken from its Latin name (Pb, Fe, Au)
Atom An Atom is the smallest particle of an Element that still retains the properties of that element.
Compounds A Compound is a substance that is made up of two ore more different elements combined chemically together.
Compounds O H H Water (H2O) H Methane (CH4) O C O C H H Carbon Dioxide (CO2) H
Compound ? O O Oxygen (O2) H H Hydrogen (H2)
When a compound is formed during a chemical reaction its properties differ from those of the elements from which it is made
Mixtures • A mixture consists of two or more different substances mingled together but not chemically combined. • Examples: Sea – water and salt Air – nitrogen, oxygen … Soil – sand, clay, humus …
Mixture vs Compound MIXTURE COMPOUND