Elements, Compounds & Mixtures

Elements

• Pure substance made of one kind of ATOM
• They are the "ingredients" to everything
• CANNOT be separated to a simpler substance
• There are over 100 on the PERIODIC TABLE

Compounds

• Chemical combination of 2 or more elements
• Can not be physically separated
• Properties of compounds are different then what made them
• Ratio of elements that makes them stay constant

•NaCl – Salt

•HCO – Vinegar

•CO2 – Carbon Dioxide

What is a Compound?

A pure substance but contains 2 or more different ATOMS

The atoms are CHEMICALLY combined in some way

Compounds CANNOT be separated by physical means

What are called Valence Electrons determines which elements can form compounds

Valence Electrons are the outermost electrons found for each element

Each element would like to have a full outer shell..but only the noble gases do

Not having a full outer-shell means the elements are "unstable" and need to combine with another element

To become stable elements will either lose, gain or share electrons with other elements. This is called chemical bonding

There are 2 types of Bonds

• Covalent
• Ionic

Covalent Bonding is where elements share electrons with another element to be stable

Ionic Bonding is where elements either lose or gain electrons to become stable

Mixtures

- Two or more SUBSTANCES NOT chemically combined.

- No reaction between substances.

Mixtures can be uniform (called HOMOGENEOUS) and can be known as solutions.
Mixtures can also be non-uniform (called HETEROGENEOUS).

- Mixtures can be separated into their components by chemical or physical means.

The properties of a mixture are similar to the properties of its components unlike compounds

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