Question

The element lithium has two stable isotopes, Li-6 and Li-7. How do the atomic structures of these two isotopes compare?
A) Both have 3 protons and 3 electrons, but Li-7 has 4 neutrons.
B) Both have 3 protons and 4 neutrons, but Li-7 has 4 electrons.
C) Li-6 has 3 protons and 3 electrons; Li-7 has 3 protons and 4 electrons.
D) Li-6 has 3 protons, 3 neutrons, 6 electrons, while Li-7 has 3 protons, 3 neutrons, and 7 electrons.

Answer 1

An isotope refers to two or more forms of a specific element that has the same number of protons but an unequal number of neutrons. Moreover, if the element is neutral, the number of protons is equal to the number of electrons. For this question, the atomic structures of Li-6 and Li-7 both have 3 protons and 3 electrons, but Li-7 has 4 neutrons.