Question

What is the difference between \[Na\] and \[N{a^ + }\] in terms of the number of electrons?
An atom of an element is represented as \[_9^{19}X\]. How many electrons and neutrons are present in this atom?

Answer 1

Hint: Atom is a tiny particle and consists of subatomic particles like electrons, protons and neutrons. The protons and neutrons are present in the nucleus. Outside the nucleus electrons were present. The number of protons gives the atomic number and the sum of the protons and neutrons gives the mass number.

Complete answer:
The atom consists of electrons, protons and neutrons. These three are subatomic particles. Nucleus is a heavy portion at the centre of the atom consisting of positively charged subatomic particles and zero charged subatomic particles.
The number of protons gives the atomic number and the sum of the protons and neutrons gives the mass number.
Sodium is an element with atomic number \[11\] and the number of electrons will be \[11\].
Sodium loses an electron and becomes a sodium ion, the number of electrons in \[N{a^ + }\] will be \[10\].
The mass number of an atom is represented on the left top of the atom and the atomic number is at left down. Given atom is represented as \[_9^{19}X\] Thus, there are \[9\]electrons and \[10\]neutrons, as the neutrons and protons give the mass number.

Note:
The number of electrons and protons will be equal in the neutral atom as the positively charged inside the nucleus and the negatively charged subatomic particles called electrons balances the atom by oppositely charged forces. The subtraction of atomic number from mass number gives the number of neutrons.