Question

The atomic number of uranium is $92$ and its atomic mass is $238$. How many neutrons does the most common atomic isotope of uranium have?

Answer 1

In order to calculate the number of neutrons we must know the atomic number and atomic mass of the isotopes of uranium. As by formula, atomic mass of element is equal to the sum of total number of electrons and total number of neutrons.

Complete step by step answer:
Uranium was discovered in year $1789.$ The atomic radius of Uranium atom:
Covalent atomic radius $=196\,(7)$ pm (Picometer)
Empirical atomic radius $=175$ pm (picometer)
Under wall’s atomic radius $=240$pm (picometer)
The Sensation energy of this atom is 194 ev. (electron volts)
The melting point of uranium $=1408$ Kelvin or $1135{}^\circ$Celsius or $2075{}^\circ$ fetrauve.
The Boiling point of Uranium is $4131{}^\circ$Celsius.
Uranium is obtained from uranium ores Such as Uraninite $\text{(U}{{\text{o}}_{\text{2}}}\text{)}$. Carnotite $\text{(}{{\text{K}}_{\text{2}}}{{\text{(U}{{\text{o}}_{\text{2}}}\text{)}}_{\text{2}}}\text{V}{{\text{O}}_{\text{4}}}\text{.1}-\text{3}{{\text{H}}_{2}}\text{O)}$, pitchblende, austenite $\text{(Ca(U}{{\text{o}}_{\text{2}}}{{\text{)}}_{\text{2}}}{{\text{(P}{{\text{o}}_{\text{4}}}\text{)}}_{\text{2}}}\text{.10}{{\text{H}}_{\text{2}}}\text{O}$ , it also obtained from monazite sand, leg nits, phosphate rock.
Pure Uranium is a silvery white and weakly radioactive metal which is harder than most of the elements uranium metal reacts with almost all non metallic elements and their compounds. On increasing the temperature their reactivity increases.
The number of elements and protons in an atom always be the same but the number of neutrons changes. When there is change on number of neutron then it is known as isotopes:
Because of the difference in the number of neutrons, different isotopes have different mass numbers.
Main isotopes of Uranium as follows:
Uranium $232$
We know electrons and protons have the same in number $92$ and different in number of neutrons.
$_{\text{92}}^{\text{P+N}}\text{U}+_{92}^{90+140}\text{U}$
This isotope of Uranium has half life $68.9$ years. It is a rare example of an even-even isotrop.
Uranium $-233$ It has one more atom neutron that is $141$
It is used in Nuclear weapons and reactor fuel.
The half life of this is only 22 minutes
Uranium $234$
It has the number of neutron $147$
Uranium $235$
It has a number of neutrons $143$ . It is the only fissile isotope that is primordial nuclear. Which if found is a significant quantity in waste.
Uranium $236$
It is a use top of uranium that is nuclear fissile with their map neutron, nor very good fertile material. It is considered as long lived radioactive waste.
Uranium $237$
Uranium $238$ This is the most common isotope of Uranium it has a number of neutrons is $156$ . This if found is nature it is a ferrite metal.
Uranium $239$
Most common isotope of Uranium is $^{238}\text{U,}{{\,}^{235}}\text{U}$ and $^{234}\text{U}$

Note: The number of protons in the nucleus of the atom is equal to the atomic number. The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom is equal to the sum of the number of protons and neutrons in the nucleus. The number of neutrons is equal to the difference between the mass number of the atom and the atomic number.