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Elementary Chemistry – From Atoms to Cannizzaro Reaction

The fundamental element that constitutes matter in all 3 states, namely, solid, liquid and gas is the atom. Atoms are the fundamental components of the universe and are too small to be seen with the naked eye. Atoms may be positively charged, negatively charged or neutrally charged. Atoms are also the smallest element of the matter. Let us try understanding the structure of atom in detail.

What Does Atom Consist Of?

The atom is divided into three main parts: protons, neutrons, and electrons. Protons and Neutrons are inside the nucleus and electron resides outside the nucleus. Protons and neutrons together are known as nucleons.

The atom consists of:

  • Protons
  • Neutrons
  • Electrons

Protons: Protons are positively charged particles that are seen inside the nucleus of an atom. It has the capacity to move freely inside an atom. The number of protons in an atom determines the atomic number of the element. Proton has an actual mass of 1.6 X 10-24g and is considered as unit positive charge and is equal to +1. Protons are denoted by ‘p’. The charge over proton is 1.6 X 10-19 coulomb.

Neutron: The mass of a neutron is 1.6 X 10-24g, which is the same as that of a proton. Neutrons contain no charge and have a relative mass of 1U. Neutrons present in the nuclei the atom varies as per the element. Neutrons are denoted by ‘n’.

Electrons: The electron carries -1e charge and is approximately equal to -1.6 X 10-14. Mass of the Electron is 9.1 X 10-24. Since it has comparatively negligible mass electrons are ignored when calculating the mass of an atom. Electrons are denoted by ‘e’.

The atomic number of the element is calculated by the formula:

Atomic Weight = number of protons + number of neutrons

The structure of the atom is as shown in the figure below. It explains the composition of the nucleus of an atom with the locations of protons and neutrons.

Pictured: Electrons are seen outside the nucleus

Cannizzaro Reaction

Cannizzaro reaction is a type of chemical reaction named after scientist Stanislao Cannizzaro which involves in the base-induced disproportionation of 2 molecules of a non-enolizable aldehyde to yield a carboxylic acid and a primary alcohol.

Cannizzaro Reaction results in one molecule of alcohol and one molecule of carboxylic acid from two molecules of a given aldehyde. Scientist Stanislao Cannizzaro in the year 1853 succeeded in obtaining benzyl alcohol and potassium benzoate from benzaldehyde.

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