1. PERIODIC TABLE
Where it all is

2. The Beginning
Law of Triads: In 1817 Johann Dobereiner noticed that the atomic weight of strontium fell midway between the weights of calcium and barium, elements possessing similar chemical properties.
In 1829, after discovering the halogen triad composed of chlorine, bromine, and iodine and the alkali metal triad of lithium, sodium and potassium
He proposed that nature contained triads of elements
The middle element had properties that were an average of the other two members when ordered by the atomic weight.

3. History
John Newlands determined a repeating pattern of every 8 elements. He called it the law of octaves.
Developed in the 1860’s
Dmitri Mendeleev arranged the first on based on Atomic Masses.
Henry Moseley Arranged the Modern Periodic Table based on Atomic Number.

4. Who was first?
There has been some disagreement about who deserves credit for being the "father" of the periodic table:
the German Lothar Meyer
or the Russian Dmitri Mendeleev.
Both chemists produced remarkably similar results at the same time working independently of one another. Meyer's 1864 textbook included a rather abbreviated version of a periodic table used to classify the elements.
Unfortunately for Meyer, Mendeleev's table became available to the scientific community via publication (1869) before Meyer's appeared (1870).

5. Mendelev’s Table
Mendeleev’s table as published in 1869, with many gaps and uncertainties

6. How is it Arranged?
Based on increasing atomic number (protons)and on electron configurations (valence)
Results in repeating chemical(valence) and physical properties (protons).
Groups or Families
Columns that go up and down. (valence electrons)
There are 18 Groups
Periods
Rows that go across
There are 7 Periods (energy levels)

7. Classification of Elements
Metals
On the left side (lower left is most metallic)
Make up ¾ of all elements
Malleable, Ductile, Conduct electricity, form positive ions.
NonMetals
On the Right side
Dull, Brittle, Insulators, form negative ions
Metalloids (Semimetals)
Found along the staircase between metals and nonmetals, have properties of both.

8. Group 1 – Alkali Metals Highly reactive Replace Hydrogen in Water
All have 1 valence electron
All are s1 (electron configuration)
Forms +1 ions

9. Group 2 – Alkaline Earth Metals
Very reactive
Don’t replace Hydrogen in Water
Readily burn in O2 when exposed to heat
Calcium makes up your bones.
Batteries get their name from this group
Have 2 Valence electrons
All are s2 – forms +2 ions

10. Transitional Metals Groups 3 to 12
These are the common metals
All have d orbitals filling
Less reactive than other metals
Copper, Silver, and Gold least reactive
Forms various positive ions
All have either 1 or 2 valence electrons

11. Boron Family – Group 13 Have 3 Valence electrons
All are s2 p1
All form +3 ions
One is a metalloid (Boron)
The rest are all metals
Metals in this group are called Poor Metals

12. Carbon Family – Group 14 Carbon family has 4 valence electrons
All are s2 p2
Composed of:
one non-metal (Carbon)
Two metalloids (Silicon and Germanium)
Two Poor metals (Tin and Lead)

13. More on Group 14 Carbon always forms 4 bonds
All known life based on Carbon
Bonds with itself easily to form chains
Computers function based on Silicon and Germanium’s unique properties
They conduct electricity but not heat
Lead and Tin are common metals
Lead (Pb) Plumbum and Tin (Sn) Stannum

14. Group 15 – Nitrogen Family
All have 5 valence electrons
All are s2 p3
Composed of:
two nonmetals - Nitrogen and Phosphorous
Two metalloids – Arsenic and Antimony
One metal - Bismuth

15. Some facts on 15 Nitrogen: Phosphorous
makes up most of the atmosphere (78%)
Critical to plant and animal life
Forms strong bonds that are used in explosives
Phosphorous
Arsenic and Antimony have been used as poisons
Bismuth used in Pepto Bismol

16. Group 16 – Oxygen Family All have 6 valence electrons Composed of:
All are s2 p4
Usually form 2 bonds
Form – 2 ions (except Polonium +2, +4 ions)
Composed of:
3 nonmetals – Oxygen, Sulfur, Selenium
1 metalloid – Tellurium
Polonium is classified as a metalloid but this is disputed by some that believe it to be a metal. It is highly radioactive.

17. Group 17 - Halogens All have 7 valence electrons All are nonmetals
All are s2 p5
Forms 1 bond
Forms -1 ions
All are nonmetals
Highly reactive
Never found in nature as single atoms
When pure will form F2, Cl2, Br2, I2

18. Group 18 – Noble Gases All have 8 valence electrons except Helium
All are s2 p6 (except Helium-1s2) e-config
Rarely form bonds
Never form ions
Helium, Neon, Argon have never been found in a compound
Krypton, Xenon, Radon can sometimes be forced to form compounds – but these are very unstable
Form bright colors when electricity runs through them

19. Actinides and Lanthanides
Called Rare Earth Metals
Not actually rare just hard to find
are synthetics
Some are radioactive (61,93-103)
All elements greater than Uranium (92) are primarily manmade but also found naturally
Some are used in medical research
Also used in electronic equipment

20. TRENDS Atomic Radius – The size of the atom.
Hard to measure due to cloud not being distinct
Smaller Up and Right
Negative Ions Larger
Positive Ions Smaller
Ionization Energy – The energy required to remove one electron, the more electrons removed, the more energy required.
Greater Up and Right
Fluorine the highest
Francium the lowest

21. More on Trends
Electronegativity – The ability of atoms to attract electrons during bonding
Greater Up and Right
Fluorine the Greatest Electronegativity
Francium the Lowest
Octet Rule – Atoms Tend to gain, lose or share electrons to have a full (s2, p6) valence energy level
Shielding Effect – The ability of inner electrons to shield valence electrons from the nucleus. Increase Down, Across Same