Q1: A magnesium atom has 12 protons and 12 neutrons, what are the atomic number, atomic mass and mass number. State (i) which one of these numbers changes during a chemical reaction and (ii) why and (iii) what would be the result of this change? Q2: When the magnesium atom in Q1 converts to an ion, it will take a noble gas configuration according to the octet rule. What is this noble gas? Q3: Illustrate the concept of isotopes in brief statements. Provide two examples where isotopes found true application in real life. Q4: What are the symbol name and atomic number of the element with Z=57? You may use the periodic table