Hydrogen gas and chlorine gas react to produce hydrogen chloride. What mass of hydrogen chloride (In grams) is formed when 31.5 g of hydrogen gas and 627.2 g of chlorine gas are reacted?

the answer to your question is c.

if you read the house of usher you should know that the house was haunted

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.