Periodic table of elements

Elements are

• pure substances which cannot be broken down into simpler substances by thermal (heat), chemical, or electrical means.
• composed of the same type of atoms. i.e. small particles that have identical chemical and physical properties.

For example oxygen gas cannot be broken down into anything simpler so it is called an element.

Water on the other hand can be broken down into the simpler substances, hydrogen and oxygen. Water is not an element.

Elements are the building blocks of matter and combine with one another in chemical reactions to form new substances called compounds. eg. water, H₂O

B. SYMBOLS OF ELEMENTS

There are about 90 naturally occurring elements.

Each element is given a name and a symbol. eg. Hydrogen, symbol H and Oxygen, symbol, O

Chemical symbols are used as a means of chemical shorthand for the elements.

• They are listed in the Periodic table.
• The first letter is ALWAYS a CAPITOL letter. eg. O for oxygen
• If the element has two letters the second letter is always lower case.

eg. The symbol for the element Cobalt is Co and not CO which is chemical formula for carbon monoxide.
eg. The symbol for the element Nobellium is No and not NO which is chemical formula for nitrogen monoxide.

All of the elements that we know and their chemical symbols are listed in the periodic table of the elements.

• The symbols of some elements are also based upon their Latin names.