1. Ch 10 The Periodic Table

2. 10.1 Using the Periodic Table
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. 10.1 Using the Periodic Table
Elements with similar properties occurred in a repeating pattern.

4. 10.1 Using the Periodic Table
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. 10.1 Using the Periodic Table
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 protons in an element. When the periodic table was arranged by increasing atomic number, all elements fit the table.
Periodic Law-states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements

6. 10.1 Using the Periodic Table
Decoding the Periodic Table
Each square on the periodic table includes:
Atomic number
Chemical symbol
Chemical name
atomic mass

7. 10.1 Using the Periodic Table
Decoding the Periodic Table
Period- Each horizontal row of elements
Group- Each column of elements.
Elements in the same group have similar properties.
Elements in the same period have the same number of electron shells

8. 10.2 Metals The Periodic Table and Classes of Elements
We break elements into three major groups
Metals
Nonmetals
Metalloids

9. 10.2 Metals Metals – found to the left of the zigzag line
Few electrons in the outer energy level
All solids at room temp. except Mercury (Hg)
Lustrous
ductile
malleable
good conductors

10. 10.2 Metals Properties of metals
Luster - describes the ability of a metal to reflect light
Malleability - describes the ability of a substance to be hammered or rolled into sheets
Ductility- describes the ability of a substance to be pulled into thin wires
Good conductors of electricity and thermal energy
Higher densities, boiling points, and melting points in general

11. 10.2 Metals Alkali Metals Group: 1 Valence Electrons: 1
Valence electron - electron in the highest occupied energy level
Reactivity : Very reactive
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

12. 10.2 Metals
Alkali metals in water

13. 10.2 Metals Alkaline Earth Metals Group: 2 Valence Electrons: 2
Reactivity: reactive but less than alkali metals
silver color, higher density

14. 10.2 Metals
Chlorophyll contains Mg; oyster shell, pearl, and cast contain calcium

15. 10.2 Metals Transition Metals Group: 3-12
Valence Electrons: varies (1 or 2)
Reactivity: much less reactive
Shiny, good conductors, higher densities and melting points (except Hg)
Some transition metals from periods 6 & 7 appear 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.

16. 10.3 Nonmetals and metalloids
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)

17. 10.3 Nonmetals and metalloids
Metalloids – found on the zigzag
outer energy level is half full
have some properties of metals
have some properties of nonmetals
sometimes called semiconductors
Semiconductors conduct electricity at high temperatures but not at low temperatures

18. 10.3 Nonmetals and metalloids
Boron Group
Group: 13
Valence Electrons: 3
Reactivity: reactive
4 metals, 1 metalloid
solid at room temp.
Aluminum (Al) is most abundant metal in Earth’s crust

19. 10.3 Nonmetals and metalloids

20. 10.3 Nonmetals and metalloids
Carbon Group
Group: 14
Valence Electrons: 4
Reactivity: varies
solids at room temp.
carbon is nature’s most important element. Found in carbohydrates, proteins, fats, and nucleic acid (DNA)
Germanium and silicon are used as conductors in computer chips

21. 10.3 Nonmetals and metalloids

22. 10.3 Nonmetals and metalloids
Nitrogen Group
Group: 15
Valence Electrons: 5
Reactivity: varies
most are solids at room temp. except N
N is 80% of the air we breathe, fertilizer

23. 10.3 Nonmetals and metalloids

24. 10.3 Nonmetals and metalloids
Oxygen Group
Group: 16
Valence Electrons: 6
Reactivity: very reactive
Oxygen (O) is 20% air and needed for substances to burn

25. 10.3 Nonmetals and metalloids

26. 10.3 Nonmetals and metalloids
Halogens
Group: 17
Valence electrons: 7
Reactivity: very reactive – most reactive nonmetals
Form salts with alkali metals
poor conductors

27. 10.3 Nonmetals and metalloids

28. 10.3 Nonmetals and metalloids
Noble Gases
Group: 18
Valence electrons: 8 (except He – 2)
Reactivity: unreactive
Colorless, odorless gases at room temp.

29. 10.3 Nonmetals and metalloids

30. 10.3 Nonmetals and metalloids
Hydrogen
Group: 1 - in group 1 only due to valence electrons
(does not share any other properties with the alkali metals)
Valence electrons: 1
Reactivity: very reactive
colorless, odorless, explosive reactions w/ oxygen