Explanation

Venus is the hottest planet in the solar system.

Venus has no moons.

The "black planet" is Venus.

The second closest planet to the sun is Venus.

The slowest-rotating planet is Venus.

Venus is similar in size to Earth.

Additional information:

Eight planets in the solar system: 

1. Mercury
2. Venus
3. Earth
4. Mars
5. Jupiter
6. Saturn
7. Uranus
8. Neptune