Suppose that scientists have discovered three new elements. All three elements are in the same group on the periodic table. The other known properties of the elements are given in the table.
Element symbol Atomic mass Physical state Boiling point
Xo 47 amu gas 215∘C
A 27 amu gas 350∘C
Zw 98 amu liquid 285∘C
The best order for the elements within the group, starting from the top and working down is ______ (Choices: Xo, Zw, A / A, Xo, Zw / Xo, A, Zw) because of the trend in the _______________. (Choices: Alphabetical order, boiling point, or atomic masses)
