Molecules: The smallest particle of an element or compound which is capable of independent existence and shows all the properties of that substance is called a molecule. In general, molecule is a group of two or more atoms that are chemically bonded together. Atoms of the same element or of different elements can join together to form molecules.
Molecules can be divided into two categories:
Molecules of Elements: The molecules of an element contain same type of atoms. Molecules of many elements are made up of one atom of that element.
Illustration: Noble gases like argon , helium
etc.
The molecules of most of the non-metals are made up of more than one atom.
Illustration: A molecule of oxygen consists of two atoms of oxygen and is known as diatomic molecule, Ozone
consists of three atoms of oxygen.
Molecules of Compounds: Atoms of different elements join together in definite proportions to form molecules of compounds.
E.g. molecule is made up of hydrogen and oxygen elements in the ratio of 1:8 by mass.
Prediction of Number of Atoms from Mass Ratio: In order to predict the number of atoms from mass ratio, divide the given mass of each element by the atomic mass of the element and calculate the simplest ratio between the obtained moles.
Example: We know that mass ratio of nitrogen and hydrogen in ammonia molecule is 14: 3. As we can see in the picture ammonia molecule is consists fo one N and three H-atoms are present hence, the formula of ammonia is .
Which of the following is the Molecule of element ? | |||
Right Option : B | |||
View Explanation |
Which of the following are the compound molecule ? (a) H2O (b) CO2 (c) O3 (d) NH3 | |||
Right Option : C | |||
View Explanation |
A compound is formed by the combination of atom of at least ______________ element. | |||
Right Option : D | |||
View Explanation |
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