1. Chapter 2: Chemistry of Life
Section 2.1: Introduction to Chemistry
Part II

2. The atoms of most elements link up with each other in different arrangements and combinations – these links are called chemical bonds.

3. When chemicals bond they form substances called chemical compounds.
Atoms form bonds in an attempt to become more stable which means they seek to have a full out shell.

4. 2 Types of Chemical Bonds
Ionic

5. Ionic Bonds
One must remember with ionic bonds the elements are constantly trying to make their outer shells stable!!!
Atoms on the left side of the periodic table tend to give up or lose electrons.
Atoms on the right side of the periodic table tend to accept or gain electrons

6. Ionic Bonds
When an atom gains or loses an electron, the result is an ion.
A negative ion has gained 1 or more electrons.
A positive ion has lost 1 or more electrons.
The strong attraction between oppositely charged ions is called an ionic bond.

7. 2 Types of Chemical Bonds
Ionic
Covalent

8. Covalent Bonds
When electrons are shared between atoms a covalent bond is formed.
The more electrons in the covalent bond, the more strongly the 2 atoms are joined.
Types:
Single bond – share 2 electrons
Double bond – share 4 electrons
Triple bond – share 6 electrons

9. Covalent Bonds Not easy to break.
A group of atoms united by covalent bonds typically acts as a single unit called a molecule.
A molecule can contain from 2 to millions of atoms!

10. Chemical formula
Shorthand notation to describe a chemical compound.
Indicates the elements that form the compound and the proportions in which they combine.
H2O2

11. Properties of Water Found in every living cell and outside most.
Vital to life
Polar molecule (see figure at right)
Good at dissolving polar and ionic compounds