The nucleus of ⁶Li is a powerful absorber of neutrons. It exists in the naturally occurring metal to the extent of 7.5%. In the era of nuclear deterrence, large quantities of lithium were processed to remove 6Li for use in hydrogen bomb production. The lithium metal remaining after removal of ⁶Li was sold on the market. (a) What are the compositions of the nuclei of ⁶Li and ⁷Li?

Verified step by step guidance

1. Identify the atomic number of lithium (Li), which is 3. This means every lithium atom has 3 protons in its nucleus.
2. Determine the number of neutrons in the nucleus of 6Li. The mass number of 6Li is 6, which is the sum of protons and neutrons. Subtract the number of protons (3) from the mass number (6) to find the number of neutrons: 6 - 3 = 3 neutrons.
3. Write the composition of the 6Li nucleus: it contains 3 protons and 3 neutrons.
4. Determine the number of neutrons in the nucleus of 7Li. The mass number of 7Li is 7. Subtract the number of protons (3) from the mass number (7) to find the number of neutrons: 7 - 3 = 4 neutrons.
5. Write the composition of the 7Li nucleus: it contains 3 protons and 4 neutrons.

Key Concepts

Isotopes

Isotopes are variants of a chemical element that have the same number of protons but different numbers of neutrons in their nuclei. For example, lithium has two stable isotopes: lithium-6 (6Li) with three protons and three neutrons, and lithium-7 (7Li) with three protons and four neutrons. Understanding isotopes is crucial for analyzing nuclear reactions and applications in fields like nuclear energy and medicine.

Nuclear Composition

The nuclear composition of an atom refers to the number of protons and neutrons it contains, collectively known as nucleons. The atomic number, which is the number of protons, determines the element, while the mass number, the sum of protons and neutrons, indicates the specific isotope. For lithium, 6Li has a mass number of 6, while 7Li has a mass number of 7, highlighting their differences in neutron count.

Natural Abundance

Natural abundance refers to the relative proportions of different isotopes of an element found in nature. In the case of lithium, 6Li constitutes about 7.5% of naturally occurring lithium, while 7Li makes up the remaining 92.5%. This concept is important for understanding the availability and applications of isotopes in various scientific and industrial processes, including nuclear reactions.