21) Which statement best describes all compounds?
A)
They can be decomposed by chemical change.
B)
They can be decomposed by physical means.
C)
They contain at least three elements.
D)
They contain ionic bonds.

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit

Which is the solubility product expression for caf2(s)?  [ca2+]/[f–]2  [ca2+][f2–]  [ca]+[f]2  [ca2+][f–]2

What causes different colors to appear in the sky? the absorption of light by air molecules the reflection of light by bodies of water the greenhouse effect in earth's atmosphere the scattering and reflection of light by dust particles