Question

How many protons and electrons are in ${}_{29}^{64}{\text{C}}{{\text{u}}^{2 + }}$ ion?

Answer 1

Hint: We know that atoms are the smallest unit of any matter. There are three subatomic particles of atoms namely, proton, electron and neutron. The nucleus is the centre of atoms. Protons and neutrons are present in the nucleus and electrons are present in orbits surrounding the nucleus.

Complete step by step solution:
First we understand the representation of an element chemically. An element is represented chemically by using both the atomic number and mass number. The chemical representation of an element X is ${}_{\text{Z}}^{\text{A}}{\text{X}}$, where A is mass number and Z is atomic number.
Let’s discuss the atomic number in detail. Atomic number is the identification of every element. None of the two elements have the same atomic number. Atomic number of elements is the number of protons present in the nucleus. In ground state, the number of protons and electrons is equal. For example, the number of protons and electrons present in a sodium atom is 11. But, in sodium ion $\left( {{\text{N}}{{\text{a}}^ + }} \right)$ the number of protons is 11 but the number of electrons is 10 (one electron lost).
Now, come to the question. Here, a copper ion is given. From the symbolic representation we get to know that the atomic number of Cu is 29 that means, the number of protons present is 29. The cupric ion $\left( {{\text{C}}{{\text{u}}^{2 + }}} \right)$ has two less electrons than the number of protons. So, the number of electrons in ${}_{29}^{64}{\text{C}}{{\text{u}}^{2 + }}$ is 27.

Hence, in ${}_{29}^{64}{\text{C}}{{\text{u}}^{2 + }}$ , number of proton present is 29 and number of electrons present is 27.

Note: It is to be noted that mass number is also used in representation of an element. The summation of the number of protons and neutrons of an atom gives the mass number. It is symbolically represented by ‘A’.