Explanation:
The given data is as follows.
Pressure (P) = 760 torr = 1 atm
Volume (V) =
= 0.720 L
Temperature (T) =
= (25 + 273) K = 298 K
Using ideal gas equation, we will calculate the number of moles as follows.
PV = nRT
Total atoms present (n) =
=
= 0.0294 mol
Let us assume that there are x mol of Ar and y mol of Xe.
Hence, total number of moles will be as follows.
x + y = 0.0294
Also, 40x + 131y = 2.966
x = 0.0097 mol
y = (0.0294 - 0.0097)
= 0.0197 mol
Therefore, mole fraction will be calculated as follows.
Mol fraction of Xe =
= 
= 0.67
Therefore, the mole fraction of Xe is 0.67.
Since nonmetals have five, six, or seven electrons in their valence shells, it takes less energy to gain the necessary electrons, and therefore form anions.
<span>C is the correct answer. Elements in the periodic table are grouped based on having similar properties. For example, the noble gases are all non-reactive and non-metallic. The electronic structure of an atom is the way the electrons are arranged within it, and this affects where they are located in the periodic table. The number of electrons in an element is the same as its group number in the periodic table (with the exception of Group 0).</span>