The atoms of some elements can exist with different masses. The number of protons in the atoms of the element is the same, but the number of neutrons is different.
Atoms with the same number of protons but different numbers of neutrons are called isotopes. For example, carbon can have three isotopes.
Carbon 12
C 6 6 protons 6 neutrons
6 P 6 N
6 P 7 N
6 6 protons 7 neutrons
6 P 8 N
Carbon 13
C 6 6 protons 8 neutrons
Carbon 14
C
Carbon-12 (6P + 6N)
: Fig. 16.7 Isotopes of carbon ? TEST TUBE
10. Two isotopes of chlorine exist: Cl–35 and Cl–37. Use the periodic table to answer the following questions:
a. What is the atomic number of chlorine? b. How many protons, neutrons and electrons does the isotope Cl–35 have? c. How many protons, neutrons and electrons does the isotope Cl–37 have? d. What do the two isotopes have in common? e. How do the two isotopes differ? f. Draw the Bohr model of the atom for each isotope. g. Write out the electronic configuration for each isotope.