Dennis Driscollo age 13, of Chula Vista, Calif., for his question:
What are elements?
Gold is an element. Silver, lead and iron are elements but steels, brass, bronze and most everyday metals are not elements. Oxygen, the gas we breathe in, is an element. Carbon dioxide, the gas we breathe out, is not an element. Liquid mercury is an element. Liquid water is not an element.
Carbon dioxide, as it name implies, is composed of carbon and oxygen both of them elements. Water as we all know, is composed of hydrogen and oxygen; both of them elements. Carbon dioxide and water then are composed of basic ingredients. And the basic ingredients are elements. Hydrogen is composed of nothing but hydrogen. Carbon of nothing but carbon and oxygen of nothing but oxygen.
The smallest particle of water is composed of two atoms of hydrogen and one atom of oxygen. When this unit is split apart it is no longer water. Plants divide carbon dioxide gas into atoms of carbon and oxygen. These atoms are reassembled by the plant along with other atoms to form particles of sugar. The particles of sugar can be broken down again into separate atoms.
An element is formed of atoms all of one kind. Hydrogen is composed only of hydrogen atoms. Oxygen is composed only of atoms of oxygen. All atoms are composed of particles. The hydrogen atom has one proton particle and one electron particle. It is the smallest of the atoms and number one on the atomic table. The oxygen atom has eight protons and eight electrons. It is number eight on the atomic table.
Twenty years ago, the list of basic elements stopped at 92. This is the number of different atoms occurring in nature. The atomic scientists have found more elements end the list of different elements is now over 100.
The number of each atom is the number of protons in its nucleus. Each proton is a particle charged with positive electricity. The number of protons in an atom is balanced with an equal number of electrons charged with negative electricity. The number of these particles gives an atom its character. An atom of gold with its 79 protons must behave very differently from an atom of neon with its ten protons.
A list of the elements is very short. What’s more, pure elements occur in nature only rarely. Most things around us are composed of two or more elements. The list of these substances and compounds is almost endless. Soap, sugary salt, cloths, wood and plastic are all composed of compounds of basic elements. These basic chemical elements are the building blocks of everything on earth and everything in the whole universe.
Under ordinary conditions only two of the basic elements are liquid bromine and mercury. Mercury is the only metal which is liquid at normal temperatures. Eleven of the basic elements are gases under normal conditions and 88 of them are solids. Of the solids 65 are metals and 13 are non‑metals.