1. The Periodic Table

2. The Father of the Periodic Table—Dmitri Mendeleev
Mendeleev was the first scientist to notice the relationship between the elements
Arranged his periodic table by atomic mass
Said properties of unknown elements could be predicted by the properties of elements around the missing element
Moseley later discovered that the periodic nature of the elements was associated with atomic number, not atomic mass

3. The Periodic Table Column = Group or Family
18 columns on the Periodic Table
Row = Period
7 rows on the Periodic Table

4. What does the information in the box tell me?1 H
1.008
Atomic Number = # of protons
Elemental Symbol
Atomic Mass = # of protons plus neutrons

5. Metals, Nonmetals, and Semi-metals
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

6. The Groups of the Periodic Table
Group 1: The Alkali Metals
Most reactive metals on the PT
Rarely found free in nature
1 valence electron
Group 2: The Alkaline Earth Metals
Still quite reactive
2 valence electrons

7. T he Groups of the Periodic Table
Groups 3-12: Transition Metals
Found freely and in compounds in nature
Usually 2 valence electrons
Group 13: Boron Family
3 valence electrons

8. The Groups of the Periodic Table
Group 14: The Carbon Family
Contains elements that can form unusual bonds (carbon and silicon)
4 valence electrons
Group 15: The Nitrogen Family
5 valence electrons

9. The Groups of the Periodic Table
Group 16: The Oxygen Family
Also known as the chalcogens
6 valence electrons
Group 17: The Halogens
Most reactive nonmetals
7 valence electrons
Group 18: The Noble Gases (The Inert Gases)
Nonreactive
8 valence electrons

10. Special Rows on the PT
Lanthanides
Actinides

11. How Are Elements Classified?
The elements are classified into three groups.
Most elements are metals, elements that are shiny and conduct heat and electricity well.
Nonmetals, all except hydrogen of which are found on the right side of the periodic table, may be solids, liquids, or gases at room temperature.
Between these groupings are semiconductors, elements that can conduct electricity under certain conditions.

12. How Are Elements Classified?
Chapter 4
How Are Elements Classified?
The periodic table below shows the distribution of metal, nonmetals, and semiconductors in the periodic table.

13. Chapter 4
Metals
The alkali metals, found in Group 1 of the periodic table, are very reactive.
The alkaline-earth metals, which include calcium, are found in Group 2 of the periodic table, and are somewhat less reactive than the alkali metals.
The transition metals, such as gold, iron, and mercury, occupy Groups 3–12 of the periodic table.

14. Nonmetals
Carbon is found in three different forms and can form many compounds.
Nonmetals and their compounds are plentiful on Earth.
Halogens, such as chlorine, are located in Group 17 of the periodic table.
Noble gases, such as neon, make up Group 18 of the periodic table. They are unreactive.

15. Nonmetals Silicon is the most familiar semiconductor. Chapter 4
Semiconductors are intermediate conductors of heat and electricity.
Silicon is the most familiar semiconductor.
Silicon is an important part of computer chips, as well as other semiconductor devices such as transistors, LED display screens, and solar cells.