Question

the element cobalt is a lustrous, gray, brittle metal. The elemt bromine is a volatile reddish-brown liquid. In a labroratory experiment, which of these would demonstrate that they have formed a compound?

a) the nickel connot be broken down into different elements.
b)the magnesium bromide connot be broken down into different elements.
c)the metallic solid is definitely an element.
d)the metallic solid is definitely a compound.