Question

Hydrogen has three naturally occurring isotopes which figure into the average atomic mass found on the periodic table (1.00974): hydrogen-1, hydrogen-2, and hydrogen-3. Which would you guess is most abundant? Explain your answer

Answer 1

The most abundant isotope of hydrogen is hydrogen-1, also known as protium, which accounts for over 99.98% of naturally occurring hydrogen, because its mass is closest to hydrogen's average atomic mass on the periodic table.

Step-by-step explanation:

The most abundant isotope of hydrogen is hydrogen-1 (protium, 1H), which has one proton and no neutrons. This abundance is reflected in the atomic mass of hydrogen on the periodic table, which is approximately 1.008 amu. Since hydrogen-1 is closest to this average atomic mass, it is the most prevalent isotope. Protium represents over 99.98% of naturally occurring hydrogen. In contrast, hydrogen-2 (deuterium, 2H) with one neutron, and hydrogen-3 (tritium, 3H) with two neutrons, are much rarer. Deuterium occurs about 1 in every 10,000 hydrogen atoms, and tritium is even more scarce and is radioactive.

Answer 2

The number following the name of the element is the number of subatomic particles inside the nucleus of the atom. This means that it is the mass number of the isotope. The average atomic mass of the element is the sum of the products of the percentage abundance and mass number of the naturally occurring isotopes.

Since, the average atomic mass of the hydrogen is nearest to 1 then, the most abundant isotope should be hydrogen-1.