Question

in a reading, you come across a lithium atom represented as li⁺. a neutral atom of lithium has 3 protons. what can you infer about the number and type of subatomic particles present in li⁺?
o this lithium atom has lost a proton, so it now has 2 protons and 3 electrons.
o the lithium atom has gained a proton, so it now has 4 protons and 3 electrons.
o this lithium atom has lost an electron, so it now has 3 protons and 2 electrons.
o this lithium atom has gained an electron, so it now has 3 protons and 4 electrons.

Explanation:

A neutral lithium atom has 3 protons. The symbol Li⁺ indicates a lithium - ion. When an atom loses an electron, it forms a positive ion. Since the atomic number of lithium (number of protons) remains the same in a chemical reaction (only electrons are gained or lost in normal chemical processes), and a neutral lithium atom has 3 protons and 3 electrons, a Li⁺ ion has lost 1 electron, so it has 3 protons and 2 electrons.

Answer:

The lithium atom has lost an electron, so it now has 3 protons and 2 electrons.