1. Parts of an atom: Label the diagram
Atoms contain 2 parts:
The atomic nucleus contains ___________ and ___________
_________ fly around the nucleus near the speed of light

2. What Atoms are made of Atoms are made of 3 parts.
Protons are found in the atomic nucleus. They have a __________electrical charge.
Neutrons are also found in the atomic nucleus. They have _____________.
Electrons are found outside of the nucleus. They have a ___________charge.

3. Different Elements = Different Atoms
Atoms of different elements are different from one another because they have _______________ of protons, neutrons, and electrons.

4. Atomic Number
The atomic number is the _________________________________ in an atom’s nucleus.
In a neutral atom (charge = 0), there are __________ numbers of positive protons and negative electrons.
If atoms ______electrons they become negative, and if they ________electrons, they become positive.

5. What causes atomic bonds?
When atoms __________________________________to one another, that is called a chemical reaction.
Why do chemical reactions happen?

6. It’s all about Potential Energy
Atoms bond to get a lower energy configuration.
Arrows indicate increasing potential energy

7. But Why? ELECTRONS DETERMINE HOW ATOMS BOND
Atoms that have a full outer energy level are very stable. This is the driving force of bonding reactions.
Atoms bond together in a way that fills their outermost electron energy level. (2 or 8)
This is the lowest energy configuration possible.

8. Types of Bonds
Type of bond
What happens
Example molecule

9. Ionic Bonds
An atom loses 1 or more valence electrons, giving it a positive charge.
Another atom gains the electron(s) and becomes negatively charged
+ & - ions attract. - + e- e- Cl e- Na e- e- e- e- e-

10. Covalent bonds
2 atoms share a pair of valence electrons H H e- e-

11. TWIST: Polar Covalent Bonds
In a polar covalent bond, a pair of electrons is shared between two atoms… unevenly
One part of the molecule now has a small – charge, and the other has a small + charge
Polar covalent
Electron Sharing
100%
Non-polar covalent
100%
Ionic

12. Recap
Atoms are made of positive protons, neutrons with no charge, and negative electrons.
The number of protons and electrons determines what charge an atom will have.
Chemical reactions occur when atoms change how they are bonded together.
Atomic bonds can be ionic, covalent, or polar covalent.
Ionic: electron(s) transferred
Covalent: pairs of electrons are shared
Polar covalent: pairs of electrons are shared unevenly.