Which statement best describes elements?

a. they are the smallest particles of any material.

b. they are composed of only one type of atom .

c. they are the most expensive materials on earth.

d. they break down easily.

? ?

B

Explanation:

An element is defined as a substance composed of only one kind of atom, while an atom is defined as the smallest particle that can exist in isolation.

The reason the answer is B is because the definition of an element is that it only has one kind of atom, but apart from that, if a substance were to contain more than one kind of atom, it would then be classified as a compound.

For example, CaCO₃ (Calcium carbonate) is a compound of calcium and carbon dioxide. The reason that most substances found in nature are compounds, is that over time all the elements were exposed to things other than themselves, and thus they reacted with different elements, forming compounds.

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.