One isotope of a metallic element has mass number 59 and 31 neutrons in the nucleus. The cation derived from the isotope has 26 electrons. Write the symbol for this cation.

Ni with +2 electron

I agree.

To write the symbol for the cation derived from this isotope, we need to determine the number of protons in the nucleus.

The number of neutrons in an atom is given by the mass number minus the atomic number. In this case, the mass number is 59 and there are 31 neutrons.

So, we can calculate the atomic number by subtracting the number of neutrons from the mass number: 59 - 31 = 28.

Since the atomic number represents the number of protons, we now know that the cation derived from this isotope has 28 protons.

Furthermore, we are given that the cation has 26 electrons. In a neutral atom, the number of protons is equal to the number of electrons.

However, a cation is an atom that has lost electrons, so the cation will have fewer electrons than protons.

Since the cation has 26 electrons, we can conclude that it has 28 protons (the same number of protons in the neutral atom), and 26 fewer electrons.

To write the symbol for this cation, we start with the element's symbol, which is determined by its atomic number. The element with an atomic number of 28 is Nickel (Ni).

Since the cation has lost 26 electrons, we write the symbol Ni and indicate the charge as +26.

Therefore, the symbol for the cation derived from this isotope is Ni2+.