Elements

Notes I picked out:
Different elements are represented by different chemical symbols
Elements are pure substances that cannot be broken down into two or more simpler substances by chemical processes or electricity.
Examples: copper
Water is not an element because it can broken down by electricity into hydrogen and oxygen.

Elements can be classified into two major groups: Metal and Non-metal
Metals exist as atoms in a giant structure and most non-metals exist as molecules
Elements that have both properties of metals and non-metals are called metalloids.
Example: silicon

Elements are made up of tiny particles called atoms.
Elements that do not exist as atoms are called monatomic elements. Their atoms are not joined together chemically.
A molecule is a group of two or more atoms that are chemically combined. The molecular formula of an element is the chemical symbols plus the number of atoms needed when a molecule of that element is formed.
Molecules formed by the combination of two atoms are called diatomic molecules. Molecules that consist of three atoms are called triatomic molecules. Molecules that are formed by four or more aims are called polyatomic molecules.