Classification of matter

THE COMPOSITION OF MATTER IN CHEMISTRY

before we discuss about matter, the first time we have to know about atom, molecule, compound, and element. Sometimes we get confused if your teacher or someone ask you about what is the difference between molecule and element? Compound and substance? Atom and element?

so Get ready for an imperfect analogy ?

If there are two or more different atoms, , it's both a molecule and a compound,

If there are two or more of one kind of atom, it's just a molecule

 

1. Atom

Atoms are the smallest bits of ordinary matter and are made from particles called protons (which carry a positive electrical charge), neutrons (which carry no electrical charge) and electrons (which carry a negative electrical charge). The protons and neutrons cluster together in the central part of the atom, called the nucleus, and the electrons 'orbit' the nucleus. A particular atom will have the same number of protons and electrons and most atoms have at least as many neutrons as protons.

2. Element

An element is a chemical substance which consists of only a single type of atoms, hence they are pure. For example, the smallest element is the hydrogen, and silver, gold, platinum are some of the commonly known precious elements. Each element has an atomic mass, atomic number, symbol, electronic configuration, etc. Although most of the elements are naturally occurring, there are some of the synthetic elements like Californium, Americium, Einsteinium, and Mendelevium. All the elements can be broadly categorized into three categories as metal, metalloids and non metals. Further, they are categorized into groups and periods based on more specific characteristics. Elements in the same group or periods share certain common characteristics, and some properties may change sequentially when you go through a group or period. Elements can be subjected to chemical changes to form various compounds; however, elements cannot be further broken down by simple chemical methods. There are atoms of the same element with different number of neutrons; these are known as isotopes of an element.

  3. Molecule

Molecules are made up by chemically bonding two or more atoms of the same element (e.g.: O₂, N₂) or different elements (H₂O, NH₃). Molecules don’t have a charge, and the atoms are bonded by the covalent bonds. Molecules can be very large (hemoglobin) or very small (H₂), depending on the number of atoms that are connected. The type and number of atoms in a molecule are shown by the molecular formula. The simplest integer ratio of atoms present in a molecule is given by the empirical formula. For example, C₆H₁₂O₆ is the molecular formula of glucose, and CH₂O is the empirical formula. Molecular mass is the mass calculated considering the total number of atoms given in the molecular formula. Each molecule has its own geometry. The atoms in a molecule are arranged in the most stable manner with specific bond angle and bond lengths to minimize the repulsions and straining forces

4. Compound

A compound is a substance formed when two or more chemical elements are chemically bonded together. Two types of chemical bonds common in compounds are covalent bonds and ionic bonds

Most elements can interact with other elements to form compounds. Hydrogen gas, for example, burns in oxygen gas to form water. Conversely, water can be decomposed into its component elements by passing an electrical current through it. Pure water, regardless of its source, consists of 11% hydrogen and 89% oxygen by mass. This macroscopic composition corresponds to the molecular composition, which consists of two hydrogen atoms combined with one oxygen atom. The properties of water bear no resemblance to the properties of its component elements. Hydrogen, oxygen, and water are each unique substances