Which of these could be separated by physical means such as distillation or filtration? a. an atom b. a mixture c. an element d. a compound?

Something that can be separated by physical means implies that there is a noticeable difference between the two components when mixed together. For example, salt water has a noticeable difference in that the boiling points of water and salt are so different that the water can be separated by evaporation. The only thing that can be separated by physical means is a mixture.

The correct answer is c

Nonmetals usually react by gaining electrons