Isotopes are atoms of the same element that differ in the number of neutrons.
Remember that all the atoms of an element have the same number of protons. So the only difference between isotopes of an element is the number of neutrons.
86 Sr means that the mass number of this isotope is 86. Also, remember that the mass number is the number of protons plus the number of neutrons.
87 Sr means that the mass number of this isotope is 87.
So, 86 Sr and 87 Sr differ 1 neutron.
Answer: 1 neutron
If the spoons touch, no heat will flow among the spoons because they are already in thermal equilibrium with each other. This is hinted by the statement "they are at room temperature" which means they all have the same temperature. Heat only flows when there is a difference in temperature.<span>
The answer will be </span><span>C. No heat will flow among the spoons
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