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

Answer:A

Step-by-step explanation:

Answer 2

All isotopes of Li have 3 protons and 3 electrons, but isotopes different in # of neutrons. Li-7 means the nucleus has 3 protons + 4 neutrons = 7 atomic mass.
So A) is the correct answer.