The answer is (1) 24. There are 26 protons in nucleus of Fe atom. There is 26 electrons in Fe atom. Fe atom loses 2 electrons and change to Fe2+ ion. So there is 24 electrons in Fe2+ ion.
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.
Answer:
A. The red side is acidic.
B. Because it has more positive hydrogen ions.
C. The blue side is basic.
D. Because it has more negative hydroxide ion.