Atoms of elements in a group on the Periodic Table have similar chemical properties. This similarity is most related to the atoms A number of energy levels
B number of valence electrons
C atomic numbers
D atomic masses

because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). they locate the types of rock that are likely to contain natural gas deposits.