Read this paragraph and answer the question below.
A chemical element is a material, which cannot be broken down or changed into another substance using physical methods. Elements may be thought of as the basic chemical building blocks of matter. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead. Hydrogen and helium are by far the most abundant elements in the universe. However, oxygen is the most abundant element in the Earth's crust, making up almost half of its mass. Just six elements—carbon, hydrogen, nitrogen, oxygen, calcium, and phosphorus—make up almost 99% of the mass of a human body.
The properties of the chemical elements are summarized using the periodic table, which powerfully and elegantly organizes the elements by increasing atomic number into rows ('periods') in which the columns ('groups') share recurring ('periodic') physical and chemical properties.
Do a web search for a periodic table of elements. Then answer the following question:
