Question

The value of A for an atom containing 12 protons, 12 electrons and 16 neutrons is

a. 24

b.4

C. 28

d. 12

e. 16

Answer 1

Answer: A = atomic number = 12

Explanation: A (atomic number) defines the chemical element. It is the numbervof protons or electrons. Neutron numbers may vary, produving isotopes of differing atomic mass. This isotope has atomic mass 28. The atomic number 12 = carbon. C28 does not really exist. If it could be produced it would be radioactive with an almost zero halflife.