History of the Periodic Table

Here's a little bit of information on how the wonderfully organized periodic table was invented. Yes, it's true; the periodic table didn't always exist :p So, first of all, we needed know some elements before we could even organize them. By 1917 we had already discovered 52 elements and it was rapidly increasing. By 1863 a total of 62 elements were discovered. The first few attempts to organize them was in the 1920s but nothing really got done.

- In 1857, Willy Odling seperated the elements into 13 different groups based on their physical and chemical properties. It had its flaws but it was a good start.

- Between 1863 and 1866 a guy named John Newlands discovered that by ordering all the known elements by their masses, every eighth element had something in common. This became known as the Law of Octaves. However, this method did not allow him to predict new elements.

BREAKTHROUGH!! YAY :)

 (Nice hair hehe)

- In 1869 Dimitri Mendeleev organized the elements according to their mass and properties. When he did this, he realized he was on to something...and indeed he was. :p
- When he listed them according to their mass, he noticed that certain properties recur periodically. (Oooh so that's why it's called the periodic table)
- He then broke the list into rows (period) and columns (group)
*So in other words, Dimitri was the first to make a periodic table
- He was able to predict the properties and characteristics of undiscovered elements very accurately
- This allowed chemists to organize and understand their data + predict new properties (which is very useful!!)

Modern Periodic Table
- The periodic table we use today is organized according to atomic numbers. (Incase you didn't notice..)
- Periodic Law: Properties of the chemical elements recur periodically when the elements are arranged from lowest to highest atomic numbers.

Major Divisions in the Periodic Table
Period: The set of all elements in a given row going across the table.
Group/Family: The set of all elements in a given column going down the table.


Chemical Families
Now that we know a little more about the history of the periodic table, lets learn about the different groups and families that can be found on the table. As you can see in the above picture there are many different types of elements and each one is separated into their own little groups. Here's a little bit more information on the different families.

*In case you didn't look at the above picture...
Alkali Metal: Elements in the 1st column (except hydrogen).
Alkaline Earth Metals: Elements in the 2nd column.
Halogens: 2nd column from the end on the right hand side. Starting with fluorine.
Noble Gases: Far right side of the table starting with helium.
Lanthanides: Elements in the 1st row shown under the table, starting with lanthanum.
Actinides: Underneath the lanthanides, starting with actinium.


Metals
- Reflect light when polished.
- Shiny and metallic lustre.
- Opaque
- Good conductors of electricity and heat
- Flexible when in sheets
- Malleable (Hammered or rolled into sheets)
- Ductile (Drawn into wires)
- Solid at room temperature (Except mercury)
- Lose electrons


Non-Metals
- Gas, liquid, brittle solid at room temperature
- Poor conductor of heat and electricity
- Solids = dull to lustrous and opaque to translucent 
- 2 types of non metals:

• Very low electrical conductive 
• Fair to moderate conductivities

Semiconductor

- Non metal with electrical conductivity, it increases with higher temperature

- Metalloids/Semimetals have properties that look more like metals than non metals

- Metal conductivity decreases with increased temperature 

- Metalloid's conductivity increases with temperature