Groups of the Periodic Table
...y are much less reactive than the first two groups but usually combine with oxygen to form oxides. The boron series is composed of metalloids and metals. Boron forms many compounds to make things like heat-resistant glass, eyewash, and antiseptic. Aluminum, which is also in this group, is very strong and does not tarnish in air. It is often used in wiring and many household items. The carbon series is very important. Carbon is the basis for all life. Silicon is used in glass and solar cells. Germanium is a metalloid and is most commonly used in transistors. Tin is important because it is resistant to rust and corrosion. Lead is the most dense element in this group, but it forms poisonous compounds. The nitrogen series has five valence electrons, which they lose very easily. The group is all nonmetals or metalloids. Bismuth is the most metallic element in the group. The chalcogens have six valence electrons. Their properties range all the way from nonmetallic to metallic. The halogens are strongly nonmetallic. They are the most active nonmetals, however. Fluorine is the most reactive element. Halogens combine with metals to make many kinds of salts. Noble gases are odorless gases. They are called inert because they do not react easily with anything. They are all found in small amounts in the Earth's atmosphere. They are so inactive because their outer energy level is full. The lanthanides are found naturally on earth and they are metallic elements. Only one in this series is radioactive. They are about as reactive as calcium, so they are actually very reactive. The actinides are all radioactive. Many of them have to be made synthetically in labs so it is difficult to study their properties. Hydrogen and Neon Henry Cavendish discovered hydrogen in 1766. He was working in London, England at the time he discovered it. It is named for the Greek words hudor meaning water and gennan meaning generate. The symbol for hydrogen is H, its atomic number is one, and its atomic mass is 1.00794 amu. Hydrogen is a nonmetal with a boiling point of -252.87 degrees Celsius and a melting point of -259.14 degrees Celsius. The electron configuration of hydrogen is 1s1....