1. Ch 10 The Periodic Table

2. 10.1 Discovering a Pattern
Dmitri Mendeleev discovered a pattern to the elements in 1896.
First he wrote the names and properties of the elements on cards.
Then he arranged his cards in order of increasing mass. A pattern appeared! 
Periodic - happening at regular intervals, like days of the week.

3. Elements with similar properties occurred in a repeating pattern.

4. Discovering a Pattern
Mendeleev predicted that elements yet to be found would fill in the gaps in his table.
He was right! Missing element Germanium (Ge) fit into his gap.

5. Changing the Arrangement
Some elements did not fit in the table by increasing atomic mass – so Mendeleev changed his table.
1914 Henry Moseley determined the number of protonsin an element. When the periodic table was arranged by increasing atomic number, all elements fit the table.
Periodic Law-Repeating chemical and physical properties of elements change periodically with the elements’ atomic numbers.

6. The Periodic Table and Classes of Elements
Metals – found to the left of the zigzag line
Few electrons in the outer energy level
All solids at room temp. except Mercury (Hg)
shiny
ductile
malleable
good conductors

7. METALS

8. The Periodic Table and Classes of Elements
Nonmetals - found to the right of the zigzag line
almost a complete outer energy level (Group 18 is complete)
more than half are gases at room temp.
not shiny
not malleable
not ductile
not good conductors (good insulators)

9. The Periodic Table and Classes of Elements
Metalloids – found on the zigzag
outer energy level is half full
have some properties of metals
have some properties of nonmetals
sometimes called semiconductors

10. Decoding the Periodic Table
Each square on the periodic table includes:
Atomic number
Chemical symbol
Chemical name
atomic mass

11. Decoding the Periodic Table
Period- Each horizontal row of elements
Group- Each columnof elements.
Elements in the same group have similar properties.
Elements in the same period have the same number of electron shells

12. 10.2 Grouping the Elements Group 1 – Alkali Metals
Elements in group 1 of the periodic table
One valence(electron in the highest occupied energy level)
Very reactive because they can easily give away the 1 electron
Often stored in oil because they react violently with water and oxygen
Soft, silver color, shiny and low density

13. Group 1 - Alkali Metals
Alkali metals in water

14. Group 2 – Alkaline Earth Metals
Elements in group 2 of the periodic table
2 valence electrons
Slightly less reactive than alkali metals because it’s harder to give away 2 electrons
silver color, higher density

15. Group 2 – Alkaline Earth Metals
Chlorophyll contains Mg; oyster shell, pearl, and cast contain calcium

16. Group 3-12 – Transition Metals
Do not give away electrons as easily as group 1 or 2
1 or 2 valence electrons
Shiny, good conductors, higher densities and melting points (except Hg)
Some transition metals from periods 6 & 7appear below the table to save space.
Elements in each row tend to have similar properties
Lanthanides- shiny, reactive metals
Actinides- radioactive , or unstable. Elements listed after plutonium do not occur naturally.

17. 10.3 Group 13 Boron Group Group 13 Boron Group 4 metals, 1 metalloid
3 valence electrons
solid at room temp.
Aluminum (Al) is most abundant metal in Earth’s crust
reactive

18. Group 13 Boron Group

19. Group 14 Carbon Group Group 14 – Carbon Group 4 valence electrons
solids at room temp.
carbon is needed in body for carbs, fats, and protein.

20. Group 14 Carbon Group

21. Group 15 Nitrogen Group Group 15 Nitrogen Group
5 electrons in outer energy level
most are solids at room temp. except N
N is 80% of the air we breathe, fertilizer

22. Group 15 Nitrogen Group

23. Group 16 Oxygen Group Group 16 Oxygen Group 6 valence electrons
Reactive
Oxygen (O) is 20% air and needed for substances to burn

24. Group 16 Oxygen Group

25. Group 17 Halogens Group 17 Halogens 7 valence electrons very reactive
Form salts with alkali metals
poor conductors

26. Group 17 Halogens

27. Group 18 Noble Gases Group 18 Noble Gases All nonmetals
8 valence electrons (except He – 2)
unreactive
Colorless, odorless gases at room temp.

28. Group 18 Noble Gases

29. Hydrogen Hydrogen 1 valence electron reactive,colorless, odorless,
explosive reactions w/ oxygen