Question

The element carbon exists in several different forms. Pure carbon can be found in the form of diamonds, coal, and the graphite in your pencil. Which statement concerning carbon is FALSE?
A) All carbon atoms have 6 protons.
B) All carbon atoms have 6 neutrons.
C) All carbon atoms have an atomic mass equal to the number of protons and neutrons.
D) All carbon atoms have an atomic number of 6.

Answer 1

Answer:

B) All carbon atoms have 6 neutrons.

Explanation:

The false statement from the given choices is that all carbon atoms have 6 neutrons.

There is a phenomenon called isotopy in chemistry.

Isotopy is the existence of two or more atoms of the same element having the same atomic number but different mass numbers due to the differences in the number of neutrons in their various nuclei.

• These atoms of elements are called isotopes.
• Carbon atoms generally have proton number of 6 which is the same as the atomic number.
• As with all atoms, the mass number or atomic mass equals the number of protons and neutrons.

For the isotopes of carbon, their number of neutrons differs.

 For example:

            ¹²₆C                           ¹³₆C                        ¹⁴₆C

The number of neutrons differs in the above isotopes.

 Number of neutrons = mass number - atomic number;

    ¹²₆C  , number of neutrons  = 12 - 6  = 6

      ¹³₆C, number of neutrons  = 13 - 6  = 7

       ¹⁴₆C, number of neutrons = 14 - 6  = 8

Therefore, based on the concept of isotopy, all carbon atoms do not have 6 neutrons.