Elements, compounds and mixtures

Elements, compounds and mixtures

What is an element

• An element is a pure substance which cannot be split into simpler substances by any chemical process.

• May consist of individual atoms e.g. copper (Cu) Or molecules composed of atoms of the same kind, e.g. oxygen (O2)

• There are 103 different elements; they can be divided into metals and non-metals

Challenge

Using your periodic table, identify five(5) metals and five (5) nonmetals along with their atomic symbols.

Properties of metals and nonmetals

What physical characteristics comes to mind when you think of metals and non metals

Common metal objects

Common nonmetal objects

What are compounds?

• A compound is a substance containing two or more different types of element bonded together chemically in fixed proportions and in such a way that their properties are changed.

• For example: magnesium + oxygen  $\rightarrow$  magnesium oxide

•  Other examples include: water (H2O), carbon dioxide (CO2)

what are mixtures

• A mixture consists of two or more substances (elements and /or compounds).

• Each component in the mixture t\retains their independent properties because they did not undergo any chemical reaction.

  
  

• For example: sand & water, salt & pepper

• sugar & water, salt & water

Home work

• Research the different separation techniques used in chemistry

• Select three (3) techniques and list one mixture that can be separated by each technique.

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RECAP

So what have we learned today?