Atoms And Molecules

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• Summary

Atom is the smallest unit of a particle.

Atomic radius is measured in nanometres.
1/10⁹ m = 1 nm

The atomic mass unit (abbreviated as amu) is unit that is used to express the atomic masses of atoms and molecule at massed of compounds.

One atomic mass unit is a mass unit equal to exactly one-twelfth (1/12^th ) the mass of one atom of carbon-12.

The atomic masses of all elements have been found relative to an atom is basically the one-twelfth the mass of one atom of carbon-12 isotope.

1. Atoms of most elements are not able to exist independently. Atoms form molecules and ions.
2. These molecules or ions aggregate in large numbers to form the matter.

IUPAC (International Union of Pure and Applied Chemistry) approves names of elements.

The first letter of the symbol is always in upper case.

Some elements were represented by the starting alphabet of its name. For instance,

• Carbon as C
• Boron as B
• Oxygen as O
• Sulphur as S
• Nitrogen is written as N and
• Hydrogen as H

Some elements have Latin names

• Copper is known as cuprum and the symbol is Cu.
• Gold as Aurium and represented by Au.
• Iron as ferrum and the symbol is Fe.
• Lead as plumbum and is represented as Pb.
• Mercury as hydrargyrum and is represented as Hg.
• Kalium is the Latin name of potassium and its symbol is K.
• Silver as Argentum and it is represented as Ag.
• Natrium is the Latin name of sodium and it is represented as Na.
• The Latin name of tin is stannum and the symbol is Sn.
• Wolfram is the Latin name of tungsten and it is represented as W