Question

A neutral atom of an element has a nucleus with nucleus charge 11 times and mass 23 times that of hydrogen. Find the ratio of number of electrons to protons present in its stable ion.
A. 1:1
B. 5:6
C. 10:11
D. 12:11

Answer 1

Hint: s we know that an atom comprises three subatomic particles i.e., electron, proton and neutrons. The mass of an atom is in its nucleus that is at the centre of the atom. Also, we need to remember that all the positive charge of the atom remains inside the nucleus. And in the outside nucleus, there are electrons are the negatively charged particles lying.

Complete step by step answer:
We already know that an atom contains the same number of protons and electrons i.e, positively and negatively charged particles. So, the number of electrons is equal to the atomic number.
Now, let’s refer to the question which states that the nuclear charge is 11 times and the mass is 23 times to that of hydrogen. This means that the protons will be equal to the number of electrons.
So, we know that the number of protons = nuclear charge = number of electrons = 11
Also, mass of neutral atom = 23 which is equal to the mass of Sodium. Then, the stable ion $N{a^ + }$ is formed by loss of one electron.
Thus, the total number of electrons in the stable ion = 11 – 1 = 10 and the number of protons in the stable ion = 11
Hence, the ratio of the electron to proton in the stable ion will be equal to 10: 11.

$\therefore $The option C is correct answer.

Note:
Here, we need to remember that neutral atoms have the same number of electrons and protons. Atoms try to be in a stable state by donation or acceptance of electrons. Here we know the sodium atom forms a stable ion $N{a^ + }$ by donating an electron.