The Periodic Table

1
The Periodic Table

• Unit IIPart 4

2
The Father of the Periodic TableDmitri Mendeleev

• Mendeleev (1834-1907) was the first scientist to
  notice a relationship between the elements
• Around 1865 he arranged his periodic table by
  atomic mass
• Said properties of unknown elements could be
  predicted by the properties of elements around
  the missing element

3
Dmitri Mendeleev
4
The Periodic Table

• Henry Moseley (1887-1915) later discovered that
  the periodic nature of the elements was
  associated with atomic number, not atomic mass.

5
The Periodic Table
Column Group or Family 18 columns on the
Periodic Table
Row Period 7 rows on the Periodic Table
6
What does the information in the box tell me?

• 1
• H
• 1.008

Atomic Number of protons and of electrons
Elemental Symbol
Atomic Mass of protons plus neutrons
7
Metals, Nonmetals, and Metalloids
Hydrogen (H) the only nonmetal on the metal side
Nonmetals are on the right of the stair-step
Metals are to the left of the stair- step
Semi-metals, metalloids, touch the
stair-step
8
VALANCE ELECTRONS

• The electrons that are in the outermost energy
  level of any atom. Examples

Hydrogen has 1 valance electron
Boron has 3 valance electrons
Oxygen has 6 valance electrons
Argon has 8 valance electrons
9
8 VALANCE ELECTRONS

• In order to feel and be stable, all atoms would
  like to have 8 valance electrons. If they dont
  already have 8 they will react very well and bond
  with others that can add up to 8. Example Oxygen
  has 6 valance electrons and reacts very easily
  with 2 Hydrogen atoms to form H2O, water.

10
The Groups of the Periodic Table

• Group 1 or 1a The Alkali Metals
• Most reactive metals on the PT
• Rarely found free in nature
• Charge of 1, 1 valence electron

11

• Group 2 or 2a The Alkaline Earth Metals
• Still quite reactive
• Charge of 2, 2 valence electrons

12
T he Groups of the Periodic Table

• Groups 3-12 or 3-12b Transition Metals
• Found freely and in compounds in nature
• Charge is usually 2 but can varyusually 2
  valence electrons

13

• Group 13 or 3a Boron Family
• Charge is 3, 3 valence electrons

14
The Groups of the Periodic Table

• Group 14 or 4a The Carbon Family
• Contains elements that can form unusual bonds
  (carbon and silicon)
• Charge is 4 or -4, contains 4 valence electrons

15

• Group 15 or 5a The Nitrogen Family
• Charge is -3, contains 5 valence electrons

16
The Groups of the Periodic Table

• Group 16 or 6a The Oxygen Family
• Also known as the chalcogens
• Charge is -2, 6 valence electrons

17

• Group 17 or 7a The Halogens
• Most reactive nonmetals
• charge is -1, 7 valence electrons

18

• Group 18 or 8a The Noble Gases (The Inert
  Gases)
• Inert means Nonreactive, dont normally react
  with other elements
• Charge is 0, 2 or 8 valence electrons

19
Special Rows on the PT
Lanthanides
We call these rare earth metals because they are
rarely found on earth.
Actinides