Problem 19 - Chemistry The Central Science

Question

(a) Give the names and chemical symbols for the three isotopes of hydrogen. (b) List the isotopes in order of decreasing natural abundance. (c) Which hydrogen isotope is radioactive? (d) Write the nuclear equation for the radioactive decay of this isotope.

Step-by-Step Solution

Answer

The three isotopes of hydrogen are: (1) Protium (\(^{1}H\)), (2) Deuterium (\(^{2}H\)), and (3) Tritium (\(^{3}H\)). In order of decreasing natural abundance: Protium (\(^{1}H\)), Deuterium (\(^{2}H\)), and Tritium (\(^{3}H\)). The radioactive isotope is Tritium (\(^{3}H\)). The nuclear equation for its radioactive decay is: \[^{3}H \rightarrow ^{3}He + \beta^- + \bar{\nu}_e\].

Step 1: (a) Naming hydrogen isotopes and their chemical symbols

The three isotopes of hydrogen are: 1. Protium: Symbol is \(^{1}H\) 2. Deuterium: Symbol is \(^{2}H\) 3. Tritium: Symbol is \(^{3}H\)

Step 2: (b) Ordering isotopes by decreasing natural abundance

The hydrogen isotopes in order of decreasing natural abundance are: 1. Protium (\(^{1}H\)) - 99.98% 2. Deuterium (\(^{2}H\)) - 0.015% 3. Tritium (\(^{3}H\)) - Trace amounts (extremely rare)

Step 3: (c) Identifying the radioactive isotope

The radioactive isotope of hydrogen is Tritium (\(^{3}H\)).

Step 4: (d) Writing the nuclear equation for radioactive decay

When the radioactive isotope Tritium decays, it undergoes beta (β-) decay. The nuclear equation for the radioactive decay of Tritium is as follows: \[ ^{3}H \rightarrow ^{3}He + \beta^- + \bar{\nu}_e \] In this decay process, a neutron in the Tritium nucleus transforms into a proton, releasing an electron (beta particle) and an electron antineutrino.