Why does the mass number equal the total number of protons and neutrons? and what is mass number of atoms expressed in the periodic table?

The mass number is equal to the number of protons plus the number of neutrons. From the periodic table, we can see that chromium has an atomic number of 24, which means its nucleus contains 24 protons. ... Therefore, the chromium-52 isotope contains 28 neutrons in its nucleus.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

c8h10 is your answerr