A Brief Look at the Periodic Table of Elements - History, Purpose and Construction
Posted: Saturday, May 02, 2009
by Connor Davidson
The periodic table ended the age of alchemy and gave birth to chemistry. I wish to show you what the periodic table is, a little of its history, what it does and why it is so important. Before we start here are some definitions:
- · Element – the simplest form of a substance; i.e. the basic building block of everything.
- · Proton and neutrons – the smaller particles found in middle of atoms.
- · Atomic number – number of protons
- · Mass number – number of protons + neutrons
- · Atom – the building blocks for everything; one atom in an element*
- · Period – the proper name for the rows in the Periodic Table.
- · Group – the proper name for the columns in the Periodic Table.
Now for the science. Below is the Periodic Table of Elements (shorted to Periodic Table normally) - I thought this picture shows it quite nicely. Do you think?
From http://www.oklascience.org
Each element on the Periodic Table is represented by a symbol. For example the first column (called the alkali metals) read from top: Hydrogen, Lithium, Potassium, Rubidium, Cesium and Francium. When writing the symbol remember: the first letter is a capital and the second is lower case.
The periodic table can be divided into two, if you draw a diagonal line between the yellows and the light greens on the right you find everything on the left of the line is a metal and everything on the right of the line is a non-metal.
Here it gets a little fiddlier: ignore the yellow part in the middle of the second table below.
From www.bbc.co.uk
The numbers refer to group number - the number lets us work out how they react. The number is actually referring to the number of electrons (see definition above) in the outside of the atom with 0 actually meaning 8.The outer layer of an atom is called the outer energy level.
The aim of all the numbered groups is to have the same number of outer electrons as group 0 which is 8. To do this they must either react to gain or lose electrons. The table this shows this:
|
Group: |
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
0 |
|
Loss/gain of electrons. |
|
1 |
2
|
3 |
4 |
3 |
2 |
1 |
0 |
The elements in group 1-3 gain electrons to have the same number of outer electrons as group 0.
The elements in group 5-7 lose electrons to have the same number of outer electrons as group 0.
Group 4 either gain or lose electrons.
Well, that's a basic look at the periodic table and how it is put together. I have tried to keep it simple- don't worry if you can't understand the last part.
Connor Davidson 05/02/09
Pic credits: BBC
Connor Davidson is a UK based writer. He writes on wide variety of topics with his main interest being science, maths and engineering.
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Feel free to reprint these articles on your website by using the reprint button. If you have any questions or comments please post them below - I read all comments.
You can keep up to date with his writings by following him on twitter: https://twitter.com/#!/Connor_Davidson.
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Top-level comments on this article: (8 total)I, also being a fellow chemist, found this article interesting, despite not being that infroamtive for me.It's simple, and easy to read.Good job!I know you have studied chemistry at a higher level than this so no wonder.Thanks for the comment.
well writtenThanks for the comment.
Way over my head, but you sounded like you know what you're talking about. Great article for fellow scientist/chemist gurus. Good job, Connor.SandraI tried to keep it as simple as possible. I guess I went over the top with the last bit.Thanks for the comment.
Connor,I somewhat remember the table from high school chemistry. The rest is beyond me but you did a good job. Interesting to read about Mendeleev.NancyThanks for the comment.
Hi Connor,I was fascinated with the article. Very interesting. I loved the warning sign...and this "Earth, Fire, Air, Water. The truth is constant"Thank you.NenitaThanks for the comment.
Huh? :-)Connor, you never cease to amaze me. I must confess, I was lost, but your display and passion deserve five stars from this simpleton. :-) Blessings to you! TeresaThanks for the comment.
Very interesting. However, it elements the man on the street. Good for the field. For me, know some things about every thing and every thing about some things.ThanksThanks for the comment.
Thanks, Connor, for the free education. You did a great job at making it simple. ~mogama~Thanks for the comment.
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