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.

a) Co-60: Protons = 27, Neutrons = 33, Electrons = 27; Electron Configuration: 1s²2s²2p⁶3s²3p⁶3d⁷4s²
b) I-131: Protons = 53, Neutrons = 78, Electrons = 53; Electron Configuration: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s²4d¹⁰5p⁶

Answer 1

Cobalt-60 (Co-60) has 27 protons, 33 neutrons, and 27 electrons. Iodine-131 (I-131) has 53 protons, 78 neutrons, and 53 electrons.

Step-by-step explanation:

The number of protons in an atom is equal to its atomic number, so Cobalt-60 (Co-60) has 27 protons and Iodine-131 (I-131) has 53 protons. The number of neutrons can be calculated by subtracting the atomic number from the mass number, so Co-60 has 33 neutrons and I-131 has 78 neutrons. The number of electrons in a neutral atom is equal to the number of protons, so Co-60 has 27 electrons and I-131 has 53 electrons.

The complete electron configuration for Co-60 is 1s²2s²2p⁶3s²3p⁶3d⁷4s² and for I-131 is 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s²4d¹⁰5p⁶.