Question

Only one isotope of this element occurs in nature. one atom of this isotope has a mass of 9.123 ✕ 10-23 g. identify the element and give its atomic mass. element

Answer 1

The atom has only one isotope which means 100 % of same atom is present in nature. The atomic mass of an element is the number of times an atom of that element is heavier than an atom of carbon taken as 12. Mass of one atom of that isotope is 9.123 ✕ 10⁻²³ g, so mass of one mole of atom that is Avogadro's number of atom is 6.023 X 10²³ X 9.123 X 10⁻²³ g=54.94 g = 55 g (approximate).

So, the atom having atomic mass 55 will be Cesium (Cs). Only one isotope of Cesium is stable in nature.

Answer 2

Answer: The atomic mass of manganese element is 54.96 g/mol

Step-by-step explanation:

To calculate the number of moles, we use the equation:

`\text{Number of moles}=\frac{\text{Number of particles}}{\text{Avogadro's number}}`

We are given:

Number of atoms = 1 atom

Avogadro's number =
`6.022* 10^(23)atom/mol`

Putting values in above equation, we get:

`\text{Number of moles}=(1)/(6.022* 10^(23))=1.66* 10^(-24)mol`

Now, calculating the molar mass of element by using equation:

`\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}`

We are given:

Given mass of element =
`9.123* 10^(-23)g`

Moles of element =
`1.66* 10^(-24)mol`

Putting values in above equation, we get:

`1.66* 10^(-24)mol=\frac{9.123* 10^(-23)g}{\text{Molar mass of element}}\\\\\text{Molar mass of element}=(9.123* 10^(-23)g)/(1.66* 10^(-24)mol)=54.96g/mol`

The element having molar mass as 54.96 g/mol is manganese.

Hence, the atomic mass of manganese element is 54.96 g/mol