1) What does H2 represent?a) Hydrogen atomb) Hydrogen molecules c) Compoundd) None of these 2) Which of the following substances is an element?a) Mercury b) Sodium chloride c) Carbon dioxide d) Hydrochloric acid
1) What does H2 represent?
a) Hydrogen atom
b) Hydrogen molecules
c) Compound
d) None of these
2) Which of the following substances is an element?
a) Mercury
b) Sodium chloride
c) Carbon dioxide
d) Hydrochloric acid










