) Selina is a scientist and is designing a portable water warmer that can help her warm up her samples while away from the lab. The device will store two chemicals separately. When she wants to warm up water, she will activate the device, which will mix the chemicals together to generate thermal energy. The thermal energy will increase the temperature of a container filled with water. Selina wants to find the best two chemicals that will generate energy in a safe and portable way. She starts by testing copper sulfate solution and zinc metal. She mixes these chemicals together in a beaker and records her observations in the table.

Time Observations

Before Combination: The copper sulfate solution is blue and zinc metal is a dull grey.
During Combination: Zinc Metal becomes dark and large amounts of thermal energy
is released.
After Combination: The Zinc is gone, a reddish-brownish residue remains, and the
solution is clear.

When copper sulfate and zinc metal interact, an atom of zinc replaces an atom of copper while the sulfate molecule, made of 5 atoms, is unchanged. How many atoms are there before and after the interaction? Select the correct answer choice.

Before: 5 atoms; after 6 atoms.
Before: 6 atoms; after 6 atoms
Before: 5 atoms; after 5 atoms
Before: 7 atoms; after 7 atoms