1. Families of Elements

2. The Periodic Table 1871: Dmitri Mendeleev created first periodic table
Arranged all the known elements by atomic mass.
Noticed that the similarities in their chemical properties appeared at regular intervals (periodic).
Moved elements into different groups if they had similar properties.
Left gaps for elements not yet discovered.
“In a dream I saw a table where all the elements fell into place as required. Awakening, I immediately wrote it down on a piece of paper.”
-Dmitri Mendeleev, 1834 to 1907
Chemist

3. The photograph shows a giant wall Periodic Table erected in St Petersburg, Russia, in 1934.
Elements in black were discovered between Mendeleev's death and 1934.

4. The Periodic Table
1913: Henry Moseley concluded that atomic number not atomic mass should be used to arrange the periodic table.
Periodic Law: The physical and chemical properties of the elements are periodic functions of their atomic numbers.

5. Families on the Periodic Table
Elements on the periodic table can be grouped into families bases on their chemical properties.
Each family has a specific name to differentiate it from the other families in the periodic table.
Elements in each family
react differently with
other elements.

6. Families on the Periodic Table
Metals
Nonmetals
Semi-conductors/Metalloids

7. Metals: Left-side of table (except for Hydrogen) Shiny
conducts heat and electricity well
can be stretched and shaped
usually solids
make cations

8. Nonmetals: Right-side of table (except for Hydrogen)
may be solid, liquid, or gas
typically dull and brittle
poor conductors
make anions

9. Semi-conductors: Where the metals and non-metals meet
also called metalloids
nonmetals that conduct under certain conditions
Only 6:
Boron
Silicon
Germanium
Arsenic
Antimony
Tellurium

10. ALKALI METALS Group 1 Hydrogen is not a member, it is a non-metal
All are metals and solid at room temp
1 Valence Electron
Create +1 ions
Soft and silvery, shiny
Very reactive, esp. with water
Conduct electricity
Image:

11. ALKALINE EARTH METALS Group 2 Metals Solids at room temp
2 electrons in the outer shell
Create +2 ions
White, silvery, and malleable
Reactive, but less than Alkali metals
Conduct electricity

12. TRANSITION METALS Metals Almost all are solids at room temp (Hg)
Good conductors of heat and electricity.
1 or 2 Valence Electrons
Can create up to 4 different cations
Less Reactive than Alkali and Alkaline Earth
Can bond with many elements in a variety of shapes.

13. BORON FAMILY Group 13 3 electrons in the outer shell Most are metals
Boron is a metalloid
Reactive
Solid at room temp

14. CARBON FAMILY Group 14 4 electrons in the outer shell
Contains 3 metals, 2 metalloids, and 1 non-metal Carbon (C)
Reactivity varies
Solids at room temp

15. NITROGEN FAMILY Group 15 5 electrons in the outer shell
Can share electrons to form compounds
Contains 2 metals, 2 metalloids, and 2 non-metals
Reactivity Varies
Nitrogen is the only gas at room temp, rest are solids

16. OXYGEN FAMILY Group 16 6 electrons in the outer shell Create -2 ions
Contains 2 metals, 1 metalloid, and 3 non-metals
Reactive
Oxygen is a gas, the rest are solids at room temp

17. Halogens Group 17 7 electrons in the outer shell Create -1 ions
Non-metals, Uus is unknown
Very reactive - are often bonded with Group 1 Alkali Metals
Has 2 gases, 1 liquid (Br), and 2 solids

18. Noble Gases Group 18 Exist as gases Non-metals
8 electrons in the outer shell = Full
Helium (He) has only 2 electrons in the outer shell = Full
Not reactive with other elements

19. Rare Earth Metals Some are Radioactive
The rare earths are silver, silvery-white, or gray metals.
Conduct electricity

20. Other Trends: Number of protons Atomic radius Atomic mass Ionic radius
Valence electrons
Number of energy levels
Atomic radius
Ionic radius
Ionization energy
(energy required to remove one electron from a neutral atom of an element)
Electronegativity
(ability of an atom in a chemical compound to attract electrons)

21. You may watch more videos about the elements at: