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?

Short answer

(a) The term 'inert gases' was dropped because these gases were found to participate in chemical reactions under specific conditions, thus contradicting their previously assumed unreactivity. (b) The discovery that triggered this change was the synthesis of Xenon hexafluoroplatinate (XePtF6) by Neil Bartlett in 1962, which demonstrated that elements in group 8 A can form compounds. (c) The group 8 A elements are now called "noble gases," reflecting their general lack of reactivity while acknowledging their ability to participate in certain chemical reactions.

Step-by-step solution

(a) Reason for dropping the term 'inert gases')

The term 'inert gases' was dropped because the gases in this group were initially thought to be completely unreactive due to their complete outer electron shells. However, it was later discovered that these gases can, in fact, participate in chemical reactions under specific conditions, such as high pressures and temperatures. Thus, the term "inert gases" was no longer accurate in describing these elements.

(b) Discovery that triggered the name change)

The discovery that triggered this change in name was the synthesis of Xenon hexafluoroplatinate (XePtF6) by the chemist Neil Bartlett in 1962. This was an important discovery because it demonstrated that elements in group 8 A can form compounds, contradicting the prior belief that these gases were completely unreactive. This event led to further research on other noble gases forming compounds and ultimately contributed to changing their group name.

(c) Current name of the group)

The group 8 A elements are now called "noble gases." This name signifies their general lack of reactivity compared to other elements while acknowledging that they can participate in chemical reactions under specific conditions. The name "noble gases" is derived from the analogy to noble metals, which are also known for their low reactivity and resistance to oxidation or corrosion.

Key concepts

Inert Gases

For many years, the noble gases were known as inert gases. This term led people to believe that these gases were entirely unreactive. Their outer electron shells are complete, which makes them stable and less likely to participate in chemical reactions. Because of this stability, it was assumed they could not form compounds with other elements.
However, as our understanding of chemistry improved, we learned that noble gases could react under certain conditions. When exposed to high temperatures or pressures, these gases can indeed form compounds. The realization that they are not completely "inert" led to the abandonment of the idea that they are "inert gases." This was a significant shift in chemistry as it opened up new exploration into possible reactions involving noble gases.
Being informed about the reactivity of noble gases makes one appreciate the flexibility and dynamism in chemical science. It also highlights the ever-evolving nature of scientific understanding.

Xenon Hexafluoroplatinate

Xenon hexafluoroplatinate ( XePtF_6 ) stands as a seminal achievement in the chemistry of noble gases. It was the first successful experiment that proved noble gases could indeed form stable compounds.
Neil Bartlett synthesized Xenon hexafluoroplatinate in 1962, a momentous event in chemistry. Prior to this, chemists believed that noble gases were unable to form compounds because of their full valence electron shells. Yet, Bartlett demonstrated that even these stable gases could be coaxed into reactivity under the right conditions.

• It involves xenon, a noble gas, and hexafluoroplatinic acid.
• The formation of XePtF_6 marked the opening of an entire new field within chemistry.

This discovery influenced subsequent experiments involving other noble gases and sparked interest in re-evaluating their chemical behavior. It emphasized the lesson that assumptions in science, no matter how long-held, should be constantly questioned and tested.

Neil Bartlett Discovery

The pivotal discovery by Neil Bartlett forever changed how we look at noble gases. Originally, these elements were considered inert due to their complete electron configuration.
Bartlett's work in 1962 revealed that the oxidation process, initially thought only applicable to metals, could also affect noble gases. This was revolutionary, underlining that noble gases are not as unreactive as previously thought.
Bartlett's experiment with xenon, which led to the creation of Xenon hexafluoroplatinate, was groundbreaking because:

• It expanded the scope of chemical reactions to include noble gases.
• His findings showed that external conditions like pressure and temperature could induce reactivity in these gases.

This experiment ushered in a new era of chemical exploration and redefined our understanding of the periodic table. It also led to the reassessment of the properties of other noble gases.

Chemical Reactivity of Noble Gases

The prior assumption that noble gases were wholly non-reactive was dispelled by discoveries that revealed they could engage in chemical reactions.
While they are indeed less reactive compared to many other elements, the noble gases hold the potential for reactivity under extreme conditions. High-pressure environments or elevated temperatures can induce noble gases to combine with other elements to form compounds.

• For instance, xenon and krypton have demonstrated the ability to form chemical bonds.
• Noble gases can exhibit an oxidation state, making compound formation possible.

Understanding the conditions under which these elements can react is crucial for advancing chemistry research. It also aids in exploring various applications, from lasers utilizing neon and helium to potential opportunities with xenon for chemical synthesis.
This discovery of reactivity does not render noble gases completely active but nuances our understanding, highlighting their potential under specific scenarios. Thus, the notion of the "inertness" of these gases was redefined, leading to the adoption of the term "noble gases."