Can you think of some important uses for chlorine?.The halogens are located in Group 17 and include fluorine, chlorine, bromine, iodine, and astatine.

There are important nonmetal families as well. Calcium is found in large quantities in limestone, and is a large component of sidewalk chalk. They have two electrons in the outer shell, which makes chemical bonding easy.Īll the elements in this family occur naturally on the earth. These metals are less reactive than Group 1, but still retain similar metallic properties. This family includes beryllium, magnesium, calcium, strontium, barium, and radium. The alkaline earth metals are located right next to the alkali metals in Group 2. Reactivity in the Group 1 alkali metals increases as you move down the group, meaning that francium would be the most reactive! Watch Potassium in Water (reaction only), from Brady Haran, The Periodic Table of Videos, to find the answer:

Do you think that potassium will be more or less reactive than sodium?.

Take a look at a short clip of Sodium in Water: They even have to be stored in oil so they do not react with the air! They are soft metals, meaning they can be cut with a butter knife. All of the metals in Group 1 have high reactivity and bond easily with other elements. This one electron makes the atom reactive. In this group, each element only has one electron in the outer shell of the atom. It has to do with the atomic structure and organization of the electrons in the atom. These metals, that include lithium, sodium, potassium, rubidium, cesium, and francium, have very similar characteristics. Group 1, located in a red color in the image above, is called the alkali metal group. Some of these groups have really special characteristics. You may see numbers or Roman numerals at the top of the periodic table - these represent those groups. There are 18 families, or groups, on the periodic table. In chemistry, we call elements grouped together in a column of the periodic table a family. If you missed or want a refresher on the previous The Periodic Table Related Lessons, find them in the right-hand sidebar.

The definition of family can vary, from groups of people that are genetically related to one another to a group of people who share a strong bond.

Periodic table families