Table 6.1 lists some clues that a chemical reaction has occurred. However, these events do not necessarily prove the existence of a chemical change. Give an example for each of the clues that is not a chemical reaction but a physical change.
Chemistry 111 Lecture Notes 2.3- Atomic number, mass number, and isotopes Isotopes Atoms of the same element but differ in the number of neutrons Share similar chemical properties Useful in decay measurements and isotopic labeling Subatomic particles (most importantly protons) differentiates one atom of a particular element to that of another element. Atomic number (Z) Number of protons in nucleus of atom All atoms of the same element have the same number of protons Listed on periodic table EXAMPLE: Beryllium (Be) atomic number on the periodic table is 4 so it has 4 protons. Mass number (A) Number of protons + number neutrons in the nucleus How to find number of neutrons Mass number –at