<span>The molecular mass of sodium oxide (Na2O) is A. 61.97894. The molecular mass of a molecule (Mr) is the sum of atomic masses of its atoms (Ar). The molecular mass of sodium oxide is: Mr(Na2O) = 2 * Ar (Na) + Ar(O). From the periodic table, Ar(Na) = 22.989769 and Ar(O) = 15.9994. The molecular mass of sodium oxide is: Mr(Na2O) = 2 * 22.989769 + 15.9994 = 45.979538 + 15.9994 = 61.97894.</span>
Explanation:
Carbon exists in several isotopes. ... Carbon has the atomic number of 6 which means that all isotopes have the same proton number. However, the number of neutrons is different, thus giving different mass numbers. Carbon-12 has 6 neutrons, carbon-13 has 7 neutrons, and carbon-14 contains 8 neutrons.
Using the periodic table, the pair of non metals that has the most similar properties would be :
Oxygen and Selenium
at the periodic table, these both located on the same period
hope this helps
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