Carbon-12 and carbon-13 are isotopes of carbon. which of the following statements is correct? they both have seven protons in the nucleus. they both have the same mass number. they both have seven neutrons in the nucleus. they both have the same atomic number.

We know that :

The Mass Number of an Element is the Sum of Neutrons and Protons.

The Atomic Number is the Number of Protons in the Nucleus of the Element

Carbon - 12 :

It has 6 Protons

It has 6 Neutrons

Mass Number of Carbon -12 is (6 + 6) = 12

Atomic Number of Carbon - 12 = 6

Carbon - 13 :

It has 6 Protons

It has 7 Neutrons

Mass Number of Carbon - 13 is (6 + 7) = 13

Atomic Number of Carbon -13 is 6

So, The Correct Answer is :

 They both have the same Atomic Number    

answer; economic order quantity;