Question

Question:Cobalt–60 and iodine–131 are radioactive isotopes commonly used in nuclear medicine. How many protons,neutrons, and electrons are in atoms of these isotopes? Write the complete electron configuration for each isotope.

Short answer

	Cobalt - 60	Iodine – 131
Protons	27	53
Electrons	27	53
Neutrons	33	78
Electron configuration	1s22s22p63s23p64s23d7	1s22s22p63s23p64s23d104p65s24d105p5

Step-by-step solution

Determine protons, neutrons, and electrons in these isotopes.  

Isotopes have a different number of neutrons but are the same elements, and have the same number of electrons and protons. Hence, observing the periodic table,

	Cobalt - 60	Iodine – 131
Protons	27	53
Electrons	27	53
Neutrons	33	78

Write the complete electron configuration for each isotope.  

From the periodic table, we can write the electron configuration as,

Cobalt-60 = 1s²2s²2p⁶3s²3p⁶4s²3d⁷

Iodine-131 = 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁵