Which of the following would 9 indicate a new substance has
been formed?
Bubbling and fizzing
occur.
Powder dissolves in
an unknown liquid
A beaker of
hydrochloric acid
evaporates after
several days
Solid iron is melted to
a liquid
Color YELLOW
Color ORANGE
Color PINK
Which one?

Bubbling and fizzing are likely to occur when a new substance is formed. The other examples are simply changing to a different form of the same substance.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.