All matter is made up of very small particles called atoms. They are small, indivisible particles that cannot be seen by the naked eye. With the advancement of technology, atoms can now be viewed through scanning microscopes (Genesis, n.d.). Protons, electrons and neutrons are the particles that can be found in an atom. Protons are positively charged particles, while the electron is negatively charged. Neutrons are uncharged particles (Genesis, n.d.). The mass of the atom is measured from the mass of the proton and neutron, and they are located at the center of the atom clumping together and called the nucleus. Protons weigh approximately 1.67 x 10-24 grams or 1 atomic mass unit (amu) and the neutron also weighs 1 atomic mass unit (Interactives, n.d.). As mentioned earlier, all elements are made up of atoms. The similarity of the elements and their differences are also characterized by the properties of the atoms.
Dmitri Mendeleev was the scientist who created the periodic table of elements. In 1868, he arranged the different known elements during his time in order of their mass. That time, there were only sixty elements, so it was not so difficult. He observed that there was a pattern of similarity in characteristics on the arranged elements. This pattern was referred to as periodicity.
In 1913, a scientist named Henry Moseley rearranged Mendeleev’s table in order of the atomic number. ...
The blocks in the periodic table have the atomic symbol at the center of each block, usually in capitalized, larger, bold-faced fonts. The atomic symbol stands for the first letter of the English name of the element, or sometimes, its Latin name. If there are two letters, meaning there is already an existing element with the symbol of only the first letter, the second letter is already written in small case. Figure 2 shows a typical block of a periodic table. Figure 2. A Typical Block in the Periodic Table of Elements (Source: science.howstuffworks.com) Periodic tables have different designs in terms of the location of the information and the type of information placed on each block. Usually, they have an example of the block to identify the parts of the block, and legends to identify the metals, non-metals and transition metals. Colorful periodic tables are much easier to understand since the colors also serve as legends making it easier to identify the elements. The atomic symbol of gold, Au, is from its Latin name Aurium. The number at the upper center of the block is the atomic number, which is representative of the number of protons of an element (Genesis, n.d.). In this case, 79 is the atomic number of gold, which means that the element has 79 protons. The number at the lower center of the block is the atomic mass of gold. Some periodic tables also include other physical properties in the blocks such as the element’s specific gravity and melting point. Again, these can be identified using the sample diagram of the blocks in the periodic table. Groups and Periods Figure 3 is a simple representation of the modern periodic table of elements. As can be seen, the elements are