Answer:
The planet you're describing is Mercury. It fits all the criteria of the question.
Note: If you're looking for another planet, Mars has a thin atmosphere and is rocky, but does not rotate slowly. Venus rotates very slowly and is rocky, but has a thick atmosphere. Earth doesn't have a thin atmosphere or rotate slowly, but it is rocky and dense.
Answer:
The Terrestrial or Inner Planets
Step-by-step explanation:
You are describing the terrestrial or inner planets of our Solar System. All of these planets, Mercury, Venus, Earth, and Mars are rocky and have a dense surface unlike the gas giant or outer planets, Jupiter, Saturn, Uranus and Neptune.
