The periodic table lists all the basic properties of all the known elements. It is fairly easy to learn to read it.
The periodic table is a table made by Dmitri Mendeleev in 1869. It shows all discovered elements in addition to their basic properties. Elements are simply substances that only contain one type of atom. Examples of elements would be gold, argon, copper, uranium, carbon, etc.
Dimitri Mendeleev. Image via Wikipedia.
Unfortunately, I couldn’t find an adequate non-copyrighted image of the periodic table online, but an excellent website that has the periodic table is Ptable. It has the full periodic table, and includes all sorts of information about valence electrons, melting points, etc.
Here is a box containing an element just like on the periodic table. I made this on Microsoft Word 2010 in about three minutes, so don’t laugh.
The element, hydrogen. Image by author.
The numbers on an periodic table are very easy to read. But before I go into that, one must first have some background knowledge of the atom.
Every atom has smaller, subatomic parts. There are three main parts of the atom—the electrons, protons, and neutrons. The protons have a positive charge, and the electrons have a negative charge. Neutrons are neutral and have no charge. Protons and neutrons are located together at the center of the atom, called the nucleus. Electrons orbit the nucleus.
The atomic number (in the photo, the number 1 in the upper left corner) is simply the number of protons there are in the element. Because all elements of the same type have the same number of protons, the atomic number alone could be used to identify the element. For example, all neon atoms have the atomic number of 10, and all lead atoms have the atomic number of 82.
All elements have a letter or two that represents them. Usually, the letter(s) come from the name. So hydrogen has a symbol of “H” because it starts with H. Helium is “He” because it has he in the name. Other elements have strange symbols, but a few can be explained. Iron has the symbol “Fe” but to explain this, you have to know that iron is sometimes referred to as “ferric.” That is why the symbol is Fe.
The name of the element is, in the picture, right under the symbol. So the name of the element whose symbol is H is hydrogen.
The atomic mass is under the name in the photo. To know the mass, you must know that protons and neutrons all have an atomic mass unit of 1. Electrons has such a small mass that it isn’t counted. So the atomic mass is just the number of all the protons and neutrons in the atom. You may be wondering why the atomic mass is a decimal. This is because, although the number of protons in an atom cannot change without changing the type of element it is, the number of neutrons can change. An atom with a different number of neutrons is called an isotope. To find the atomic mass, scientists find the abundance of each isotope in nature. They use the abundance of each isotope to find the average atomic mass. So, pretend that imaginary element X has two isotopes, one with an atomic mass of 100, and the other with an atomic mass of 101. Say that 80% of all element X’s found in the world have a mass of 100, and only 20% have a mass of 101. This means that the average atomic mass of element X is 100.2, by using the formula: (mass of isotope1 x abundance) + (mass of isotope2 x abundance) Notice that since the 100 mass isotope is more common, the atomic mass of element X is closer to 100 than to 101.
That is basically all there is to reading a basic periodic table. I hope you learned something new today!
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