Lesson 1: Elements, Compounds and Mixtures

Elements:
-cannot be split into 2 or more simpler substances, which have identifiable characteristics social to themselves
-can be grouped into 3 groups: metals, non-metals and metalloids due to their properties
-are made up of tiny particles called atoms
-Metals are ductile

Compounds:
-always has chemical reaction
-2 or more elements that make a new substance
-can only be broken down into simpler substances by electricity as well as chemical reactions

Mixtures:
-2 or more substances that are mixed together but not chemically combined
-no chemical reactions
-physically combined
-no fixed ratio/ proportion
-does not lose its own characteristics
eg.         salt+water
             =salty water --> still salty, still wet
-separable into components by physical methods

* In science, sometimes, specific terms are required. However, in some case, more general terms are appropriate.
eg.
    2 or more elements that are chemically combined make a compound.
    2 or more substances that are not chemically combined make a mixture.