(SME) What are Elements? Lesson

What are Elements? 

Elements are the simplest form of matter; they are composed of only one type of atom and cannot be broken down into a simpler form by chemical means. Elements occur as metals, nonmetals and metalloids which we arrange in a periodic table by their chemical properties. There are 118 known elements in the universe, but only 98 of those occur on Earth with only 80 of those being in a stable form. The remaining elements are radioactive and undergo nuclear decay and break down into other stable elements.

Some elements are found in nature as pure substances. Elements such as gold, sulfur, copper, carbon and many others are found in their native state. Other elements, such as lithium, sodium, and potassium, are so reactive that they are only found as compounds combined with other elements. No matter in which state they are found, we use elements everyday to make the products and materials that make our life easier.

Metals

Metals are found on the periodic table to the left of the staircase. If you look at the periodic table below, the staircase is shown in black, metals are shown in purple. Notice that most of the periodic table is composed of metals. Think of a metal that you have come into contact with, perhaps your silverware which is probably stainless steel (iron and carbon with chromium), or maybe wire, which is often made of copper. Common characteristics of metals include a metallic luster, or shine. Metals are good conductors of heat and electricity and can be easily combined with other metals to form alloys. They are malleable, which means they can be hammered into thin sheets, like gold foil. Metals are also ductile, meaning they can be drawn into wires. Finally, metals are generally solid at room temperature with mercury being the notable exception to this rule; it is a liquid. In the diagram below, transition metals have been outlined in purple. Transition metals have many of the same properties as metals, but form bonds differently than non-transition metals.

 

 

Non-Metals

Non-Metals are found on the periodic table to the right of the staircase (plus hydrogen which is on the left). If you look at the periodic table to the right, non-metals are shown in red. Most of the non-metals that you will come into contact with are gases. Nitrogen is the most common gas in the atmosphere at 78%, followed by oxygen which is only 21%. Characteristics of non-metals are generally the opposite of metals. Non-metals rarely have a luster and are generally gases at room temperature. Because of this they are neither malleable nor ductile, and are poor conductors of heat and electricity.

Metalloids

Metalloids are found on the periodic table on either side of the staircase. In the periodic table to the right, they are shown in green. Metalloids are also called semi-metals and share characteristics of both metals and non-metals. Metalloids often look shiny, but they tend to be more brittle and are not generally malleable or ductile. Metalloids are not good conductors like metals, nor are they good insulators like non-metals, instead they are semiconductors.

Elements make up all of the materials that are around us. They make up the air that you breathe, the food you eat, the water you drink and even your own body! In sports we use elements to form compounds that allow athletes to perform at a higher level. Different combinations of elements allow athletes to jump higher, run faster, hit further and throw and catch with greater accuracy. In this lesson we will see how elements are used in sports and how they form many of the products that athletes rely on every day.  

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