When the Moon passes between Earth and the Sun, covering all or part of the Sun; occurs when the Sun, the Moon, and Earth directly line up usually lasts for less than 12 minutes. 1. Seasons
2. Solar Eclipse
3. Lunar Eclipse
4. Moon Phases

solar eclipse

Explanation:the moon covers the earth and the sun covers the moon

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.