Question

An element has an atomic number 30. Its cation has 2 units positive charge. How many protons and electrons are present in the cation?

Answer 1

Hint: You should recall that an atom having atomic number 30 is zinc. The atomic number of an atom is equal to the number of protons present in it.

Complete step by step solution:
Zinc is an atom having an atomic number 30.
The number of protons in an atom is equal to its atomic number and the number of electrons is equal to the number of protons.
That means the zinc atom has 30 electrons and 30 protons.
Now, as the question is saying it has a 2 unit positive charge, which means +2 positive charge. The positive charge means we have removed electrons from its outermost shell.
We are given here 2 units of positive charge, which means we have removed two electrons.
Initially, there were 30 protons, those will remain the same but removing 2 electrons will decrease the electron count from 30 to 28.

Therefore, we can conclude that an element has an atomic number 30, having its cation two units of positive charge consisting of 30 protons and 28 electrons in the cation.

Note: We should know that number of neutrons (35) present in the Zn atom (atomic number 30) can be calculated by subtracting the number of protons (30) from its atomic mass (65).