Problem 79 - Chemistry Central Science

Question

Until the early 1960 s the group 8 A elements were called the inert gases; before that they were called the rare gases. The term rare gases was dropped after it was discovered that argon accounts for roughly \(1 \%\) of Earth's atmosphere. (a) Why was the term inert gases dropped? (b) What discovery triggered this change in name? (c) What name is applied to the group now?

Step-by-Step Solution

Answer

The term "inert gases" was dropped because they were found to be not entirely unreactive, contrary to initial beliefs. The change in name was triggered by the discovery of xenon hexafluoroplatinate \(XePtF_6\), the first compound formed with a noble gas, synthesised by British chemist Neil Bartlett. The group is now called noble gases, reflecting their low reactivity but acknowledging that they can form compounds under specific conditions.

Step 1: Answer (a) - Reason for dropping the term "inert gases"

The term "inert gases" was dropped because it was discovered that these gases are not entirely unreactive. The elements in this group were initially believed to be chemically inactive, but later it was found that some of them can indeed participate in chemical reactions under specific conditions.

Step 2: Answer (b) - Discovery that triggered the change in name

The discovery that triggered the change in the name of the Group 8A elements was the synthesis of xenon hexafluoroplatinate \(XePtF_6\), the first compound ever formed with a noble gas, by British chemist Neil Bartlett. This event demonstrated that elements in this group are capable of forming chemical compounds, contrary to earlier beliefs.

Step 3: Answer (c) - Current name for the group

Today, the group that contains elements like helium, neon, argon, and others is called the noble gases, reflecting their low reactivity while also acknowledging that under specific conditions, they can form compounds.