1. Periods: Energy Levels (n)
Each row in the periodic table is called a “period”
The period corresponds to a specific energy level of the atom
The top row, Period 1, is closest to the nucleus, the next one down is Period 2, etc…until you end with Period 7.
Level 1: s
Levels 2 and 3: s,p
Levels 4 and 5: s,p,d
Levels 6 and 7: s,p,d,f

2. Groups: Valence Electrons
Each column in the Periodic Table is called a “group”
Each element in a group has the same number of electrons in their outer energy level (the valence level).
The electrons in the outer shell are called “Valence Electrons”
Red: Group Orange: Group Yellow: Group 13
Green: Group Sky Blue: Group Baby Blue: Group 16
Dark Blue: Group Purple: Group 18

3. Valence Electrons
Valence electrons are the electrons in the highest occupied energy level of the atom.
Valence electrons are the only electrons generally involved in bond formation (which we will talk about in the next unit!)

4. Bohr Atomic Structures
Electron Configuration of Na: 1s22s22p63s1
The first energy level contains 2 electrons. (s orbital…1s2)
The second level contains 8 electrons. (2s and 2p orbitals…2s22p6)
How many electrons do you see in the outermost level? 3s1… 1electron!
This is the Valence number. Sodium has 1 Valence electron.

5. Pattern: Families
Elements in column share similar traits, and are called families:
These columns are also called groups.

6. The Alkali Metals 1 valence electron Highly reactive with water
Form ionic compounds
Do not occur in nature as pure elements (always in compounds)

7. Alkaline-Earth Metals
Have 2 valence electrons
Reactive, but less reactive than alkali metals
Are ductile, malleable and have a silvery luster
Form alkaline (basic) solutions) when put in water

8. Transition metals… and inner transition metals
Are less reactive than groups 1 and 2.
Tend not to react in water.
Are malleable and ductile, but still harder than group 1 & 2.
Tend to be solids at room temperature.
Are good conductors of electricity and heat.
**Inner transition metals tend to be radioactive

9. Nonmetals Poor conductors of heat and electricity
Often are found as gases or liquids, sometimes solids.

10. Halogens Are nonmetals
highly reactive with metals- most reactive is fluorine, least reactive is astatine
Mostly exist as gases or liquids (except At -solid)
Have 7 valence electrons

11. Noble gases At room temperature, exist as gases.
Are completely unreactive
Have full s and p orbitals
Are odorless, colorless, nonflammable

12. Metalloids Tend to be solids
Have properties similar to both metals and nonmetals
Tend to be semiconductors (which means they are useful for technological uses)

13. Valence Electrons:
The outermost s & p electrons

14. Ions Ionization energy
Charged atoms that become charged by losing or gaining electrons
Ionization energy
Energy necessary to make an ion by removing an electron from a neutral atom

15. Rule #1 to remember!
When an element loses an electron, we can think of it as being given away, which is a good thing or POSITIVE thing to do.

16. Group 1 Elements H, Li, Na, K, Rb, Cs, Fr
Achieve a stable octet (full outer shell) by losing 1 electron, which forms a +1 ion
H+ , Li+ , Na+ , etc…

17. Group 2 Elements Be, Mg, Ca, Sr, Ba, Ra
Achieve a stable octet by losing 2 electrons, which forms a +2 ion
Be2+, Mg2+, Ca2+, etc…

18. Rule #2 to remember!
When an element gains an electron, we can think of it as it is being stolen from another ion, which is a bad or NEGATIVE thing to do.

19. Group 7 Elements F, Cl, Br, I, At
Achieve a stable octet by stealing (gaining) 1 electron, which forms a -1 ion
F-, Cl-, Br- , etc…

20. Group 6 Elements O, S, Se, Te, Po
Achieve a stable octet by stealing (gaining) 2 electrons, which forms a 2- ion
O2- , S2- , Se2-, etc…