MULTIPLE CHOICE QUESTION This atom is called lithium -7 Why does it have this name? It has 7 subatomic particles. It has 7 protons. Its atomic number is 7. Its mass number is 7.

## Step 1: Identify the significance of the name "lithium-7"### The name "lithium-7" refers to the mass number of the lithium atom, which is the total number of protons and neutrons in the nucleus.## Step 2: Verify the mass number of lithium-7### Lithium has an atomic number of 3, meaning it has 3 protons. For a mass number of 7, the number of neutrons must be . Thus, lithium-7 has a mass number of 7.## Step 3: Evaluate the options### A. It has 7 subatomic particles: Incorrect, as lithium-7 has more than 7 subatomic particles (3 protons, 4 neutrons, and electrons).### B. It has 7 protons: Incorrect, as lithium has 3 protons.### C. Its atomic number is 7: Incorrect, as the atomic number of lithium is 3.### D. Its mass number is 7: Correct, as explained in Step 2.