1. Periodic Table of the Elements

2. Father of the Periodic Table
Dmitri Mendeleev ( )
Mendeleev organized the elements by the properties.
He noticed a repeating pattern in the ~60 elements known at the time when he organized them by atomic mass!

3. Gallium
Germanium

4. Two Years Later…

5. Father of the Modern Periodic Table
Henry Moseley ( ) –in 1913, through his work with x-rays, Moseley discovers the actual nuclear charge of the elements, which we now call atomic numbers. Moseley then rearranges the periodic table by increasing atomic number. This is the periodic table we use today- the modern periodic table.

6. Periodic Table of the Elements
The elements are ordered by the number
of protons they have in their nucleus
Atomic Number

7. Periodic Table of the Elements
Elements are listed by increasing protons.
But grouped by reoccurring properties

8. Periodic Table Vocab Periods - horizontal rows “side to side”
Groups or Families – vertical columns “up and down”.
Valence electrons – outermost electrons, farthest from the nucleus. Chemical properties depend on valence electrons.
Elements in the same group have similar properties!

9. Metals Left of “stair step” Good conductors of heat and electricity
Ductile (can be made into thin wire) and Malleable (can be hammered into thin sheets)

10. Nonmetals Right of “stair step”
Generally poor conductors of heat and electricity
Brittle (shatters if you hit it with a hammer)

11. Metalloids Touch the “stair step” (except Aluminum.)
Have properties of both metal and nonmetals.
Metalloids only conduct electricity under certain conditions, which make them useful in the semi-conductors industry.

13. Group 1: Alkali Metals Alkali Metals Highly reactive metals
React violently with water!
One valence electron
Never found in elemental form in nature
(You have to store them coated in mineral oil to keep them from reacting!
Alkali Metals

14. Group 2: Alkaline Earth Metals
Still reactive, but not as much as the alkali metals.
2 valence electrons

15. Group 3-12: The Transition Metals
Transition Metals - metallic elements that have varying properties and belong to group 3 through 12 of the periodic table

16. Groups 3-12: The Transition Metals
Inner Transition Elements- The inner transition metals are the two rows of elements that appear below the main body of the periodic table.
Lanthanides - shiny, metallic elements with atomic numbers 57 through 71.
Actinides - metallic elements with atomic numbers 89 through RADIOACTIVE

17. Groups 13-16 Group 13- The Boron Family -3 valence e-
Group 14- The Carbon Family – 4 valence e-
Group 15- The Nitrogen Family – 5 valence e-
Group 16- The Oxygen Family – 6 valence e- (aka Chalcogens)

18. Group 17: The Halogens
Halogens - elements that combine with most metals to form salts*
7 valence electrons
These elements are diatomic molecules (2 atoms bonded together) in their natural form.

19. Group 17: The Halogens
Halogens are highly reactive, and can be harmful
Fluorine is the most reactive element in existence, even attacking glass
. It is a corrosive, highly toxic gas.
Chlorine and iodine are both used as disinfectants for drinking water, swimming pools, fresh wounds, dishes, and surfaces.

20. Group 18: The Noble Gases
Noble gases – gaseous elements with EXTREMELY low reactivities
8 valence electrons