The sun of the protons a D neutrons in the nucleus of an atom is called the ATOMIC MASS
<em><u>examples of metalloids :
</u>Boron,Silicon ,Germanium are some metalloids ...
<u>what they do:
</u>they are used to form the semiconductors and these semiconductors are used in modern computer technology like in circuits ,chips and computer based gadgets... :) <u>
</u></em>
The best answer is the first option. A bike rusting is an example of a chemical change since rusting is a chemical reaction. New substances are formed from this reaction. On the other hand, other choices given are just physical changes because only the shape or the physical form of the substances are being changed.
