Answer:
Pure Substances.
Explanation:
Elements and compounds are both examples of pure substances. A substance that cannot be broken down into chemically simpler components is an element.
The (2) calcium atom, because when looking at the periodic table, we see that the calcium atom is in a location where according to the periodic table, has the lower electronegativities in respect to the other three choices. We see that it also has a lower electronegativity value than the others. Electronegativity is the attraction constant for the electrons in a chemical bond. The higher the electronegativity, the higher the attraction of the electrons. Fluorine has the highest electronegativity with 4.0.
D. 100%, extremely sure. Because Newton's 3rd law states every force has an equal and opposite reaction.
