oxygen and silicon I believe
No because they have the same number of protons not neutrons. fine, their mass nos are equal but isotopy is due to different number of neutrons.
Answer: option C. HF
Explanation: A polar bond is a covalent bond between two atoms where the electrons forming the bond are unequally distributed. Fluorine is more electronegative than hydrogen so the electrons in the bond are more closely associated with the fluorine atom than with the hydrogen atom.
Answer: The gas generated by two antacid tablets has a smaller volume.
Explanation:
Since the antiacid is the limiting reagent, we know that the more tablets there are, the more gas there will be.
This means that there will be more gas generated by the four antiacid tablets when compared to the two antiacid tablets, which gives us that the gas generated by the two antiacid tablets has a smaller volume.