Learning Objective: To learn about the molecular mass and its calculation from atomic weights.
Skill Level – Intermediate
Prerequisites:
Related –
Chapter: Structure of an Atom
Author's Note: In the previous section, we learnt how to calculate the atomic weight for an atom of an element. In this section, we will learn how to use that information to find the molecular mass. A molecule can be formed from homonuclear (same type of atoms, like in H2) or heteronuclear (different types of atoms, like in H2O) atoms.
Finally, we learn how an atom's mass is fully concentrated in its nucleus and how small the volume of the nucleus is compared to the total volume of an atom. Then we arrive at the most important component of an atom, occupying the roomy space, the electrons, giving the atom that reactive character.
Molecule and Molecular Mass
When atoms combine, they form a molecule. Therefore, a combination of similar atoms creates homoatomic molecules, and dissimilar atoms give heteroatomic molecules.
For example, if two identical H atoms combine, it forms one H2 molecule.
Whereas the combination of two similar atoms (Hydrogen) with one dissimilar atom (Oxygen) forms one water (H2O) molecule.
Many atoms also choose to remain neutral and unreactive. E.g., He, Ar.
Molecular mass is the sum of the masses of all the atoms in the molecule, denoted as m.
The mass of the atoms is measured in the atomic mass unit, a weighted average of all the element's naturally occurring isotopes.
The sum is represented in amu (μ) or Da unit.
For example:.....
Almost 99.94% of the ......
The nucleus is dense, and its volume....
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Next: The Electrons - An Atom's Reactive Component
