Elements, Compunds & Mixtures

The properties of a compound are usually different
from its constituent elements

Its constituent elements are always combined in a
fixed proportion by mass

Elements or compounds burn adn combine with
oxygen to form one or more new compounds

A compound is a substance which is made up of
two or more different elements chemically combined
together.

Certain elements and/or compounds can combine to form
new compounds when they are in contact with one another

Decompositon occurs when more complex compounds are heated to break them down into simpler compounds

Compounds can be broken down by:
-heating
-passing electric current
-when exposed to light

A mixture consists of two or more different substances that
are mixed but not chemically commbined together

Properties of Mixtures:
-when a mixture is formed, no chemical reacttion occurs
-a mixture has the properties of its constituent substances
-a mixture can br separated easily by physical methods(ie with out involving chemical reaction
-the components in mixturres are not mixed in any fixed proportion

An element is a substance which cannot
be broken down into two or more simpler
substances by chemicla methods

Metals- shiny, can be polished
-solids
-Mallaeble & ductile
-High density
-High melting and boiling points
-Good ability to conduct electricity and heat

Non Metals -usually dull
-Mostly liquid or gas, some are solids
-Brittle for solids
-Low density
-Low melting and boiling points
-Poor ability to conduct electricity and heat

Scientists have organised all the discovered elements
into a tale called the Periodic Table