The Periodic table can also be divided into several families of elements each having similar properties. For our purposes we will define the following ten families: Alkali metals. The alkali metals, found in group 1 of the periodic table, are highly reactive metals that do not occur freely in nature. These metals have only one electron in their outer shell. Therefore, they are ready to lose that one electron in ionic bonding with other elements. As with all metals, the alkali metals are malleable, ductile, and are good conductors of heat and electricity. The alkali metals are softer than most other metals.
Water is found in many places on Earth including on the surface of the planet, within rocks below the surface, and in the atmosphere. Water travels between different areas of the Earth through the water cycle. About 70% of the Earth surface is covered with water, and most of that is the ocean. Only a small portion of the Earth's water is freshwater, which is found in rivers, lakes, and groundwater. Freshwater is needed for drinking, farming, and washing. In addition to liquid water, water is also present on Earth in the form of ice. Without water, life as we know it would not exist.
About 71% of Earth's surface is covered with water, mostly by its oceans. The remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earth's polar regions are covered in ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack.