are elements found in compounds and molecules
Two oxygen atoms join together to make an oxyen molecule. Most of the oxygen in the air is in this form. Hydrogen and chlorine also have molecules with two atoms. Some elements have molecules with more than two atoms. Sulfur atoms can make molecules of eight atoms joined together. Chemical compounds are very different from mixtures: The elements in a chemical compound can only be separated by destroying the compound. Some of the differences between chemical compounds and mixtures of elements are illustrated by the following example using raisin bran and Crispix.. Any substance that contains only one kind of an atom is known as an element. Because atoms cannot be created or destroyed in a chemical reaction, elements such as phosphorus (P 4) or sulfur (S 8) cannot be broken down into simpler substances by these reactions. Example: Water decomposes into a mixture of hydrogen and oxygen when an electric current is passed through the liquid. Hydrogen and oxygen, on the other hand, cannot be decomposed into simpler substances. They are therefore the elementary, or simplest, chemical substances-elements. All compounds are molecules but not all molecules are compounds. Molecular hydrogen (H 2), molecular oxygen (O 2) and molecular nitrogen (N 2) are not compounds because each is composed of a single element. For many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements —earth, water, air, and fire—by the action of a life-force (vis vitalis) that only organisms possessed. Water (H 2 O), carbon dioxide (CO 2) and methane (CH 4) are compounds because each is made from more than one element. The smallest bit of each of these substances would be referred to as a molecule. For example, a single molecule of molecular hydrogen is made from two atoms of hydrogen while a single molecule of water is made from two atoms of hydrogen and one atom of oxygen. A molecule is formed when two or more atoms join together chemically. A compound is a molecule that contains at least two different elements. Mellitic acid, which contains no C-H bonds, is considered a possible organic substance in Martian soil. C-C bonds are found in most organic compounds, except some small molecules like methane and methanol, which have only one carbon atom in their structure. Compounds. A compound is made when atoms of different elements join together by chemical bonds. This means that compounds will always exist as molecules, not separate atoms. The diagrams show some molecules of common compounds. Elements are made up of atoms, the smallest particle that has any of the properties of the element.John Dalton, in 1803, proposed a modern theory of the atom based on the following assumptions. 1. Matter is made up of atoms that are indivisible and indestructible. 2. All atoms of an element are identical.
Yes