1. You need to remember some basic things
Chemistry Review
You need to remember some basic things

2. The Atom
Smallest possible unit that maintains properties of the element
Made of:
Protons – positively charged particles
Neutrons- neutral particles
Together form the atomic nucleus
Electrons- negatively charged particles
Each element has a unique number of protons (atomic number)

4. Electron Orbitals/Shells
Electrons are found in characteristic areas around the nucleus, called an orbital
Each one represents a different energy level
Simplifying things, orbitals are grouped into “shells”

5. Electron Shells The innermost shell is filled first
The outermost shell is called the valence shell

6. The first shell has only 1 orbital, so it can hold only 2 electrons
Electron Shells Con.
The first shell has only 1 orbital, so it can hold only 2 electrons

7. Represents 1 Orbital. Each orbital gets 1 electron before any orbital in the shell gets a 2nd
The 2nd/3rd Shell
Consists of 4 orbitals, so each shell can hold 8 electrons

9. Draw on your Whiteboard
A neutral boron atom (for the nucleus you can just write B)
A neutral fluorine atom

10. Using the Periodic Table
Ignore the D block (the metals)
The row tells you the # of shells the atom should have
The column tells you the # of valence electrons a neutral atom should have in its valence shell

11. Please add these to your table!

12. Practice using the “short cuts” Draw
A neutral magnesium atom
A neutral phosphorus atom

13. Ions: Atomic Charge Charged atoms + ions = more protons than electrons
- ions = more electrons than protons

14. Draw the ions on your Whiteboard
Na+
Si2-

15. Filling Valence Shells
Generally chemical reactions occur that fill valence electron shells
Either by gaining/losing electrons OR
By sharing electrons with other atoms

16. Lewis Structures
Atoms almost always will end up with 8 electrons in their valence shell (may be lone pairs or shared electrons)**
So an atom that normally has 6 valence electrons needs to get 2 more from bonding
(only showing the valence electrons)

17. The column can be used to figure out how many bonds an atom will normally form