To which of the three main chemical classes does Mercury (Hg) belong? a) It's not an element in the periodic table
b) Metalloids
c) Non-metals
d) Metals

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)

Who determined the nature of chemical bonds?

Mr. rose asked his student to draw a quadrilateral with four unequal sides. an example of this kind of quadrilateral