Which of the following are FALSE about periods on the periodic table. 1.Elements having similar properties are in the same period.
2.Atoms of elements in the same period have the same number of valence electrons.
3.Elements in a period are arranged by increasing number of protons.
4.Each period is given a name such as Alkali Metals or Halogens

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

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.