Approximately how many elements combine in different ways to make compounds?

Approximately two elements may combine to form compounds, but there may be cases where more than two elements combine to form compounds.

Explanation:

In chemistry, the term compound is defined as a substance formed by the union of at least two elements. There are cases where more than two elements come together to form a compound, but we can say that approximately two elements are used for compound formation. An example of compound is shown in the chemical formulas H2O and FeS represent the compounds water and ferrous sulfide.

one negative thing it that it can kill water animals. another negative thing is it can cause the destruction of ecosystem. one way water pollution can be reduced is to conserve energy.

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.