Question

Calculate the number of electrons, protons and neutrons in 1 mole of ${}^{16}{O}^{-2}$ ions.

Answer 1

Hint: Take the help of Avogadro number. Multiply the number of electrons, protons and neutrons in one ${}^{16}{O}^{-2}$ ion to the Avogadro number.

Complete Step by step solution:
Let us first find out the number of electrons, protons and neutrons in one ${}^{16}{O}^{-2}$ ion.
A neutral ${}_8^{16}O$have 8 electrons, 8 protons and 8 neutrons.
But because of $-2$charge ${}^{16}{O}^{-2}$ ion have two extra electrons than that of${}_8^{16}O$. So the number of electrons becomes 10, proton 8, and neutron 8.
Now to obtain a particle number for one mole, we use Avogadro’s rule. According to this rule one mole of a substance is equal to $6.022x{10}^{23}$ units of that substance (such as atoms, molecules, or ions). This number $6.022x{10}^{23}$is known as Avogadro's number or Avogadro's constant.
Now to calculate number of electron, proton and neutrons in 1 mole ${}^{16}{O}^{-2}$ ion, we will multiply number of electron, proton and neutrons in one ${}^{16}{O}^{-2}$ ion to Avogadro’s number i.e.$6.022x{10}^{23}$.
Now the number of electron in one mole ${}^{16}{O}^{-2}$ ion = 10 x $6.022x{10}^{23}$
= $6.022x{10}^{24}$
Number of proton in one mole ${}^{16}{O}^{-2}$ ion = 8 x $6.022x{10}^{23}$
 = $48.176x{10}^{23}$
Number of neutrons in one mole ${}^{16}{O}^{-2}$ ion = 8 x$6.022x{10}^{23}$
=$48.176x{10}^{23}$

Therefore in 1 mole of ${}^{16}{O}^{-2}$ ions, number of electrons is $6.022x{10}^{24}$, number of protons is $48.176x{10}^{23}$ and number of neutrons is $48.176x{10}^{23}$.

Note: Be careful while counting electrons basically. As the given species is an anion so the number of electrons will be more than that of a neutral atom.