1. Sec Periodic Table

2. The First Periodic Table
Elements organized on the periodic table
1800s- As more and more elements discovered, a way of organizing them became more important

3. Mendeleev- published periodic table where elements placed in order of increasing atomic mass
Created “element cards”- inspired by favorite card game solitaire
Element cards- contained element name, atomic mass, basic properties, and some compounds the element formed

4. When Mendeleev placed elements in order of increasing atomic mass, he noticed that certain properties repeated themselves
These properties repeated in a predictable pattern- also called a “periodic” pattern
Mendeleev then placed elements with similar properties in the same vertical column- called groups/families

5. Mendeleev was forced to leave holes in his periodic table- these holes were left for undiscovered elements
Due to the organization of his table, Mendeleev was able to predict the properties of these undiscovered elements
Once the elements that fit into these holes were discovered, they matched the properties Mendeleev predicted almost perfectly

6. The Modern Periodic Table
The modern periodic table is organized by increasing atomic number
What was atomic number?
In general, the modern table is very similar to Mendeleev’s table, with only a few differences
Only a couple of elements were switched

7. Generally speaking, elements increase in mass as you move from left to right
Can you pick out any that break this trend?

8. Horizontal rows= periods
Vertical columns= groups/families
Elements in same family have very similar properties- react in similar ways
The periods at the bottom (Lanthanides and Actinides) are actually meant to fit into the table- just separated for convenience

9. Group 1- Alkali metals
Group 2 – Alkaline earth metals
Groups 3-12 Transition metals
Group no name!
Group 16- Chalcogens
Group 17 – Halogens
Group 18- Noble Gases
Actinides
Lanthanides

10. Some Group Characteristics
Alkali Metals- all have 1 valence electron
Hydrogen is at the top of this group but is not an alkali metal- it is a nonmetal
Why is it even in this group?
Soft, gray metals- all violently reactive with water
Alkaline Earth Metals- all have 2 valence electrons
Also fairly reactive with water, but not as much as the alkali metals

11. Group 13- Family beginning with Boron- all have 3 valence electrons
Group 14- Family beginning with Carbon- all have 4 valence electrons
Group 15- Family beginning with Nitrogen- all have 5 valence electrons
Chalcogens- Family beginning with Oxygen- all have 6 valence electrons, slightly reactive

12. Halogens- Family beginning with Fluorine- all have 7 valence electrons- most reactive group of nonmetals
Noble Gases- All have full valence shells, He has 2, the rest have 8 valence electrons, colorless, ordorless gases, highly unreactive

13. Table with Lanthanides and Actinides

14. Electron Configuration and the Periodic Table
Due to the arrangement of the modern periodic table, there is a perfect pattern found that can be used for electron configuration
Atomic number = number of….?
For neutral atoms, atomic number would also be the same as what?

15. Each period= energy level
Once at the end of the period (Noble Gases) energy level is full
As you move from left to right, the number of electrons increases (from one element to another, it increases by 1 electron)

16. For elements in the same family, the number of valence electrons is the same
What were valence electrons?
Due to this pattern, we are able to use the periodic table as a “map” for electron configuration

17. The periodic table is the answer key for electron configurations
Each section of the periodic table corresponds to a subshell type
s section- first two columns- how many electrons can an s subshell hold? (How many orbitals- electrons?)

18. p section- contains 6 columns- how may electrons can a p subshell hold?
d section- contains 10 columns- how may electrons can a d subshell hold?
f section- contains 14 columns- how may electrons can a f subshell hold?

19. s subshell section- begins in level 1- begins with 1s
p subshell section- begins in level 2- begins with 2p
d subshell section- begins in level 3- begins with 3d
f subshell section- begins in level 4- begins with 4f

21. Get out periodic tables- we’re going to label them to use them as keys for electron configuration!