What is the Periodic Table?

The periodic table is a chart that scientists use to classify elements. Elements are substances that are made of molecules of the same atoms. Elements cannot be broken down into other substances that can still retain their properties on their own.

The elements in the periodic table are placed in a certain position based on their molecular properties. Since the molecular properties of an element determine the element’s physical and chemical properties, similar elements will be placed in the same rows, columns, or sections.

Periods

Rows of the periodic table are known as periods. There are 7 periods in total, each having elements with similar molecular(and therefore physical and chemical) properties. Moving from left to right, the atomic number of each period increases by one.

Period 1 contains 2 elements: hydrogen and helium. Periods 2 and 3 contain eight elements, and are known as short periods. Periods 4-7 contain 18-32 periods, and are known as long periods. 

Groups

The columns of the periodic table are called groups. There are 18 total groups, all numbered from left to right.

Group 1(except for helium) is the leftmost group, and consists of the alkaline metals.  Alkaline metals are metals that react with water to form alkaline solutions. Besides being very reactant, alkaline metals are shiny and soft.

Group 2 consists of the alkaline earth metals. Alkaline earth metals are also very reactive, though not as reactive as the group 1 elements. Excluding Beryllium, alkaline earth metals are all soft and shiny like alkaline metals in group 1.

Group 17 consists of the halogens. Halogens are nonmetals that react well with alkaline metals.

Group 18 consists of the noble gasses. Noble gasses, which are also known as inert gasses, are unreactive. Because noble gasses do not form chemical reactions, they are commonly used. Examples are helium in balloons, neon in florescent lights, and fluoride in lasers and photographic flash lamps.

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Metals

Metals are solid, shiny substances. Metals generally have high melting and boiling points, and are excellent conductors of electricity and heat. Metals are also malleable(they can bend without breaking) and ductile(they can be stretched into wires without breaking). Metals on the periodic table are generally located on the left and center. Moving to the right, the elements gradually lose metallic properties.

Transition metals are metals with the same properties; they are hard, shiny, malleable, ductile, tough, and conduct heat and electricity. They have high boiling/melting points and densities. Transition metals also form complex ions, and have more than one possible charge(for example, Iron can have a charge of 3+ or 2+). Transition metals are located in the center of the periodic table.

Non-metals

Non-metals can be any of the three physical states of matter. Non-metals are usually not shiny, and are poor conductors. Nonmetals are also poor in malleability and ductility. They have low boiling points and melting points. Non-metals are located on the far right side of the periodic table(except for hydrogen, which is on the top-left).

Metalloids

Metalloids are substances that have a mixture of metallic and non-metallic properties. There are seven known metalloids: boron, silicon, germanium, arsenic, selenium, tellurium, and astatine. Metalloids are located on the right side of the periodic table between the metals and non-metals.

How is the Periodic Table helpful?

The Periodic Table can be helpful in many ways. It makes it easier for people who want to learn more about and element by showing them some properties of the element. It is also organized by order of density, which can help compare and contrast elements. Another way it is organized is by properties. Rows and Columns of elements have similar properties. This also helps comparing and contrasting elements. The Periodic Table is helpful to chemists and other scientists.