They may be of different forms (due to different arrangements of atoms) but they consist of only a single type of element.Ī mineral is a chemical compound, often in crystalline form, and usually abiogenic, i.e.
Allotropes are associated with elements, not compounds.
They are made up of only one type of element - carbon. For instance, carbon forms allotropes such as coal, graphite, and diamonds. Some of the compounds crucial to life are water, sodium chloride, carbon dioxide, etc.Īn allotrope of an element pertains to any of the pure substances formed by only one type of element although these substances could differ in structure. Many of the elements that occur naturally on Earth are chemically combined. The elements in a compound are held together by chemical bonds. For instance, the combination of sodium and chlorine atoms results in the formation of table salt or sodium chloride. All compounds are substances but not all substances are compounds since pure elements are also chemical substances.Įlements form a compound. SubstancesĪ substance pertains to that which has a definite chemical composition and distinct properties and made up of elements in combination with another or the same elements. The 0.85% is comprised of other elements such as potassium (0.4%), sulfur (0.3%), sodium (0.2%), chlorine (0.2%), and magnesium (0.1%). These major elements make up 99% of the mass of the human body. In human body, the most abundant elements by mass are as follows: oxygen (65%), carbon (18.5%), hydrogen (9.5%), nitrogen (3.2%), calcium (1.5%), and phosphorus (1%). The most common elements in living things are carbon, hydrogen, oxygen, and nitrogen. The processes believed to have primordially produced the natural elements are the nucleosynthesis in the Big Bang, stellar nucleosynthesis, explosive nucleosynthesis in supernovas, and cosmic ray spallation. Those having an atomic number beyond 94 are produced artificially. Elements having an atomic number below or equal to 94 occur in nature. Thus, a total of 118 elements have been identified so far. Common examples of elements are iron, copper, silver, gold, hydrogen, carbon, nitrogen, and oxygen.Īt present, 94 are natural elements whereas 24 are synthetic. For example, carbon is an element comprised of atoms having the same number of protons, i.e. This means that all atoms that make up the element would have the same number of protons. An element would have the same number of protons in their atomic nuclei. An atom is the smallest unit of matter and the fundamental building block of a chemical element. A chemical element refers to the pure substance of one type of atom.
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