What is an atom Grade 9?

An element is a substance that is made entirely of one type of atom. For example, the element sodium is made up of only sodium atoms. A molecule is a substance that contains two or more atoms chemically joined, such as H2,O2.

Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions.

Atoms are the smallest unit of matter that can‘t be broken down chemically. Molecules are groups of two or more atoms that are chemically bonded. Ions are atoms or molecules that have gained or lost one or more of their valence electrons and therefore have a net positive or negative charge.

Atoms are defined as “the basic building blocks of matter”. It is the smallest constituent unit of matter that posses the properties of the chemical element.

Cells are made of proteins, which are a type of molecule, and water, which is another molecule, and other things which are all made of molecules. … Proteins are made of carbon, hydrogen, oxygen, and other elements. So we know that the molecules that make up the cells of the body are made of atoms.

Proteins are one of the primary constituents of living matter. They consist of long chains of amino acids, which are bonded together by peptide linkages and thus called polypeptides. There are about 20 amino acids, and the atoms most prevalent in these are carbon, hydrogen, oxygen, nitrogen, and sulfur.

Although amino acids may have other formulas, those in protein invariably have the general formula RCH(NH2)COOH, where C is carbon, H is hydrogen, N is nitrogen, O is oxygen, and R is a group, varying in composition and structure, called a side chain.

In addition to carbon, hydrogen, and oxygen atoms, all proteins contain nitrogen and sulfur atoms, and many also contain phosphorus atoms and traces of other elements. Proteins serve a variety of roles in living organisms and are often classified by these biological roles.