What is an element? Elements are all around us. The element iron is in everything from bridges to safety pins. Electric wire is made from the element copper. Cans are made from the element aluminum. The lead in pencils is not really lead. It is graphite. This is the element carbon. Even the air we breathe is made of elements. It is mostly nitrogen and oxygen. These wires are made from the ele…
It took a long time for scientists to understand what elements are. Ancient Greeks such as Aristotle thought that there were only four elements—air, fire, earth, and water. For many years, most people believed these ideas. This picture from 1545 shows an alchemist at work. He is using a furnace to heat a water bath. But then came Robert Boyle, an Irish chemist. In the 1650s, he prov…
The periodic table shows the elements by atomic mass. The table starts with the lightest element. And it ends with the heaviest. Hydrogen is the lightest element. It has one proton and one electron. Next is helium. It has two protons and two electrons. Lithium has three protons and electrons, and so on. (The number of protons or electrons in an element's atom is called its atomic number.) …
There are ninety-two elements found on Earth. But only a few are very common. Most elements are found only in small quantities. Oxygen and silicon are the most common elements in the ground. This is because many rocks are made mainly of a substance called silicon dioxide. This substance is a combination of silicon and oxygen. The ground beneath our feet is made mostly from just eight eleme…
The periodic table can be divided into two main types of elements. These are metals and nonmetals. Most elements are metals. This shows only the metals in the periodic table. Metals conduct electricity and heat. Many are strong, shiny materials. They are often hard to melt. But, not all metals are like this. Some, such as sodium and potassium, are soft. Mercury is a metal, too. It is liqui…
There are eighteen nonmetals. Twelve are gases. Five are solids. One (bromine) is a liquid. Nonmetals are a varied group. But they do have some things in common. They are insulators rather than conductors. This means electricity and heat do not easily pass through them. Solid nonmetals are rigid. If you shape or stretch them, they break. Nonmetals do not form salts with acids. The elements co…
We have seen that Earth has only ninety-two elements. But there are millions of different substances. Most of these come from compounds. This means they are mixes of two or more different elements. Elements are the building blocks for compounds. A compound is made of two or more different atoms joined together. There are many ways to join two or even three different elements together. Many common…
acid (ASS id) — a substance that turns litmus paper red and makes salts with metals. Weak acids are sour-tasting, strong acids can burn. alchemist (AL kur mist) — a type of ancient scientist who did chemical experiments to try and find the secret of eternal life, and how to turn other metals into gold atomic number (uh TOM ik NUHM bur) — the number of protons or electrons tha…
A History of Super Science: Atoms And Elements. Andrew Solway. Raintree, 2006. Elements: What You Really Want to Know. Ron Miller. Twenty-First Century Books, 2006. From Greek Atoms to Quarks: Discovering Atoms. Sally Morgan. Heinemann Library, 2007. Periodic Table: Elements with Style! Adrian Dingle. Kingfisher Books, 2007. www.webelements.com/webelements/scholar/index.xmll Select any element fr…