Question

What is the mass number of an ion with 105 electrons, 157 neutrons, and a 1 charge?

Answer 1

Mass number of the ion is 263

Step-by-step explanation:

Mass number = number of protons + number of neutrons

Here the ion has +1 charge. Hence the precursor element or atom must have 1 extra electron than than the ion.

Now, number of protons are same with number of electrons in an atom. Positive charge only produces when one electron is removed from the atom. Therefore number of protons remain same for both the precursor atom and the ion.

So the ion has total 106 protons.

Hence mass number of the ion = 106 + 157 =263

Answer 2

Alright, first you have to understand that the mass number is simply the number of neutrons + the number of protons.

However, they've only given you the electrons and the neutrons. Assuming that you meant "1 charge" and "+1 charge" that means you've got 106 protons and 157 neutrons.

Mass number = neutrons + protons
= 106+157
= 263