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Question

Answers

a.) u

b.) A

c.) M

d.) n

Answer
Verified

To find the symbol of atomic mass unit , we need to know what is this atomic mass unit mean by:

The mass of an atom is called atomic mass. It is measured in terms of atomic mass unit (amu).

Atomic mass unit (amu) is the one -twelfth mass of Carbon - 12 isotopes. It is also known as unified atomic mass (u).

We can convert atomic mass unit (u) can be converted into gram by the following equation:

${ 1u=1.66\times { 10 }^{ -24 }g }$

For example, the mass of one atom of Carbon is 12 u.

Mass of one atom of Oxygen is 16 u

Mass of one atom of Chlorine is 35.5 u.

Therefore, ‘u’ symbol represents the unit of atomic mass, amu.

Now, we can go to a much broader concept, which is the mole concept.

Mole concept gives that 1 mole is defined as the mass of the avogadro number of particles (molecules).

Avogadro number is also represented as ${ N }_{ A }$.

${ 1{ N }_{ A }=6.022\times { 10 }^{ 23 } }$

Universally accepted value of avogadro number is ${ 6.022137\times { 10 }^{ 23 } }$.

So, there are seven significant figures in avogadro number.

For example, in 1 mol of ${ O }_{ 2 }$, there are ${ 2\times }$ Avogadro numbers of atoms.

In 1 mol of ${ H }_{ 2 }{ O }$ , there are ${ 3\times }$ Avogadro numbers of atoms.

Now, we can have a look at the term atomicity, which is given by the number of element atoms present in a molecule.

For Example: atomicity of ${ O }_{ 2 }$ is 2 , atomicity of ${ S }_{ 8 }$ is 8.