Atoms and Molecules Notes

• The symbols of a chemical element are abbreviations that are used to denote a chemical element.
• They are of one or two letters with the first letter (only) capitalized.

Dalton’s Symbols of Elements:

• Dalton was the first scientist to use the symbols to represent elements in a short way.
• Dalton’s symbols for elements were difficult to draw and inconvenient to use.

History:

• A molecule is the smallest particle of a substance (element or compound) which has the properties of that substance and can exist in the Free State.
• It is an electrically neutral group of two (or more) atoms chemically bonded together.
• The force which holds the atoms together in a molecule is called bond.

Molecules of Elements:

• The molecule of an element consists of two (or more) similar atoms chemically combined together.

For example: