Question

How many neutrons are there in the stable atom of aluminium?

Answer 1

Hint The answer to this question is dependent on the concept of chemistry which makes use of formula to find the number of protons, neutrons and electrons which is based on the periodic table and is given by, number of neutrons = mass number – number of protons.

Complete step – by – step answer:
We are familiar with the concepts of atoms, its structure, composition and also the properties about it from the basic concepts of chemistry that we learnt in lower classes.
Let us now see in detail about those concepts so that we can deduce the correct answer.
- An atom is the smallest particle that can exist which builds the entire universe. It is composed of a central nucleus which has positively charged species called protons and the neutral species called neutrons.
- The electrons that are negatively charged are revolving around the orbit of the nucleus.
- The protons are nothing but the one which gives the atomic number and always the number of protons is equal to the number of electrons and therefore they are equal.
- Neutrons and protons together make up the mass of an element and these neutrons present can be calculated using the mass number which is given by the formula, number of protons = mass number – number of neutrons.
- Therefore, the atomic number of aluminium atoms is 13 and thus the number of protons in this atom will be 13.
- The most stable form of aluminium has mass number 27 and therefore, by using the above formula, we have
${{n}_{n}}=m-{{n}_{p}}$
$\Rightarrow {{n}_{n}}=27=13=14$
Thus, there are a total of 14 neutrons present in stable form of aluminium.

Note: Note that the small amount of Aluminium – 26 occurs in nature which is radioactive but the half life is too short to survive as a primordial nuclide and thus it decays into a stable form that is magnesium – 26.