Question

What is the number of subatomic particles in iron?
A) No. of protons= No. of neutrons= No. of electrons$ = 30$
B) No. of protons$ = 26$ and No. of neutrons=No. of electrons$ = 30$
C) No. of protons=No. of electrons$ = 26$ and No. of neutrons$ = 30$
D) None of these

Answer 1

Hint: We have to remember that the iron is an element which is placed in transition metals or in d block elements having atomic number\[26\], the electronic configuration of iron can be represented as \[\left[ {Ar} \right]3{d^6}4{s^2}\].The electrons lies outside the nucleus whereas protons lies inside the nucleus.
Representation for isotope of an iron:\[^{56}F{e_{26}}\]
Where $56$=Mass number and $26$= Atomic number

Complete answer:
To solve this question, we must know what subatomic particles are.
Subatomic particles are the particles present in an atom which are neutrons, protons and electrons.
${\text{No}}{\text{. of protons}} = {\text{Atomic number of an element}}$
${\text{No}}{\text{. of electrons}} = {\text{Atomic number of an element}}$
${\text{No}}{\text{. of neutrons}} = {\text{Mass number - No}}{\text{.of protons}}$
Since atomic number of \[Fe\]=\[26\]
Therefore,
No. of protons=\[26\]
No. of electrons =\[26\]
No. of neutrons= \[56 - 26{\text{ }} = 30\]
Option A) this is an incorrect option as the number of subatomic particles can never be the same for any element.
Option B) This is an incorrect option as the number of protons and electrons are the same for an element and the number of neutrons are different.
Option C) this is a correct option as we shown above which says that no. of protons and no. of electrons are equal in an atom and number of neutrons is the difference between mass number and no. of protons. Therefore, No. of protons= No. of electrons i.e. $26$ and No. of neutrons$ = 30$.
Option D) this is an incorrect option as we got a correct option C.

Note:
We have to remember that the atomic mass is approximately double the atomic number. No. of protons is equals No. of electrons which is the atomic number of an element or atom. Protons carry a positive charge whereas electrons carry negative charge and neutrons are neutral species that have no charge.