In a neutral atom, the number of protons is equal to the number of electrons.
Given that the charge on the ion of the element is -1. This means that there is one electron more than the number of protons in the element.
The atomic number = Number of protons = 57 -1 = 56
Element with atomic number 56 is Barium.
Mass number of the element = Number of protons + Number of neutrons
= 56 + 80 = 136
So the identity of the species:
Answer: D) More moles of ions are present in a given volume of 0.10 M than in the same volume of 0.10 M NaCl.
Explanation:
A electrolyte is a solution that dissociates completely when dissolved in water. The ions act as good conductors of electric current in the solution.
More is the number of ions , more will be the conductance and hence the solution will be a better conductor of electricity.
0.10 M aqueous solution of is a better conductor of electricity as it dissociates to give three ions whereas 0.10 M aqueous solution of
dissociates to give two ions only.
Thus 0.10 M aqueous solution of sodium sulfate, , is a better conductor of electricity as more moles of ions are present in a given volume of 0.10 M
than in the same volume of 0.10 M