The Periodic Table

The periodic table was created by Dmitri Mendeleev in 1869. It was created to help categorize the known elements, ordering them by their atomic weight. The table also suggested that there were elements yet to be discovered by science.

To date, scientists have discovered or created 118 different elements. 

An element is a substance made up of only one type of atom. Many elements mix together to form other substances. For example, 1 oxygen atom bonds with 2 hydrogen atoms to make water. 

Each element is assigned a number on the periodic table. The number represents the number of protons that atom contains. While hydrogen has 1 proton, copper has 29 protons and gold has 79 protons.

The periodic table also contains information about how heavy each element is. The atomic weight is calculated by combining the number of protons and neutrons in the nucleus of the atom.

Each element gets an alphabetic symbol. Many symbols make sense, for example, O is the chemical symbol for oxygen, however some are based on Latin names. The name for gold in Latin is Aurum and its chemical symbol today is Au. 

The first 5 elements were created during the Big Bang. Heavier elements needed to be made in stars where the huge pressure and high temperatures caused nuclear fusion, forcing lighter elements to fuse together and create new elements. 

Scientists started creating new elements in 1939. They do this by colliding existing elements at high speeds. It sounds simple but it’s actually incredibly difficult and uses vast amounts of energy. So far, scientists have created 26 new elements. 

Alkali and alkaline earth metals make up the 2 left–hand columns on the periodic table. As the name suggests, these elements are present as metals in their pure form. Alkali metals are metals that are generally unstable, particularly in the presence of water. 

Alkaline earth metals are usually more stable. 

Beryllium is an alkaline earth metal with 4 protons. It is vital to the aerospace industry as not only is it one of the lightest metals, it also has a high melting point, perfect for constructing spacecraft. 

The alkaline earth metal strontium has 38 protons. Strontium flakes are added to fireworks and flares to give them a red color. When combined with iron, it can make a magnet.

Calcium is an alkaline earth metal with 20 protons. One of the most abundant elements found on Earth, it is vital to life on Earth. Calcium is also found in bones, teeth, and shells. 

Alkali metal potassium has 19 protons. An abundant element on Earth, it is mainly used for fertilizers. It is essential to life, however potassium is not found in its pure form on Earth because it reacts violently with water. 

Lithium is an alkali metal with 3 protons. Around 30% of all lithium used for industry is used to produce batteries. While excellent at storing energy, it is highly reactive, so it is important to dispose of lithium batteries safely. 

Unlike what the name suggests, rare earth metals are relatively common. However, these metals bond and diffuse with other minerals very easily, making them difficult to isolate. All actinide metals are radioactive.

Many of the elements in the actinide metal group are also man–made. 

Terbium is a rare earth metal with 65 protons. A soft metal, terbium is so soft that it can be cut with a knife. As an oxide, terbium is used in fluorescent lights. 

A rare earth metal with 67 protons, holmium is used in delicate laser surgeries. It has unusual magnetic properties, and when combined with other elements, it gives red or yellow coloring to glass and cubic zirconia.

Praseodymium is a rare earth metal that has 59 protons. It can be used to give industrial glasses a protective, yellow colored coat. It’s also used to make the permanent magnets found in electric motors and generators.

Americium is an actinide metal with 95 protons. Created in 1945 by American scientists, it is highly radioactive. A very small amount is used in smoke detectors, as the element reacts to smoke present in the air.

Actinide metal plutonium has 94 protons. Plutonium is known as the element, along with uranium, that creates the nuclear bomb. Highly radioactive, it is used to create energy in nuclear power plants.