One mole is always the same number: 6.02 * 10^ 23.
So, one mole of cars = 6.02 * 10 ^23 cars; one mole of pencils = 6.02 * 10^23 pencils; one mole of atoms = 6.02 * 10^23 atoms; one mole of molecules = 6.02 * 10^23 molecules.
So, all the options are correct: one mole of calcium ions has 6.02 * 10^23 representative particles, such as one mole of calcium nuclei and one of calcium atoms.
One-
The 6 is the only significant figure.
An objects ability to do work is measured by its mechanical energy, or the sum the objects kinetic energy and potential energy. Mechanical energy is due to the position or movement of an object. The formula for mechanical energy is mechanical energy=kinetic energy + potential energy.