PLEASE CAN SOMEONE EXPLAIN this FOR ME WHAT IS RADIOACTIVE ISOTOPES AND ANSWER THIS QUETION? A nitrogen atom has 7 protons and most common isotopes of nitrogen has 7 neutrons. A radioactive isotopes of nitrogen has 8 neutrons write the atomic number and mass number of this radioactive nitrogen as a chemical symbol with a subscript and superscript.

Explanation:

We already know that the mass number of an atom is the sum of the number of protons and the number of neutrons.

So, the mass number of this isotope is;

Number of protons = 7

Number of neutrons = 8

Mass number = 7 + 8 = 15

Hence, the isotope is;

c is the answer because when something is left after something evaporates that shows the chemical change.