Problem 79 - Chemistry The 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

(a) The term "inert gases" was dropped because these elements were found to possess some reactivity and could form compounds under certain conditions. (b) The discovery of xenon hexafluoroplatinate by Neil Bartlett in 1962 triggered the change in name. (c) The group 8A elements are now called "noble gases" due to their relatively low reactivity.

Step 1: Answer (a) Why was the term inert gases dropped?

The term "inert gases" was dropped because scientists found that the elements in this group aren't completely non-reactive or inert. Some compounds can be formed by these gases under certain conditions, meaning they have a certain degree of chemical reactivity.

Step 2: Answer (b) What discovery triggered this change in name?

The discovery that initiated the change in the name of the group 8A elements from "inert gases" to another name was the formation of the first noble gas compound (Xenon hexafluoroplatinate) by the British chemist Neil Bartlett in 1962. This compound showed that the noble gases could indeed react and form compounds under the right circumstances.

Step 3: Answer (c) What name is applied to the group now?

After the discovery of the chemical reactivity of the group 8A elements, they are now commonly referred to as the "noble gases" due to their relatively low reactivity and their refusal to form compounds under normal conditions.

Key Concepts

Inert gases

The term "inert gases" was used for the group 8A elements because it was believed that they did not react with other elements. These gases include helium, neon, argon, krypton, xenon, and radon. Their outer electron shells are full, making them stable and initially believed to be non-reactive. However, this term was later changed when it was discovered that they do react under certain conditions. The revised name reflects this newfound understanding.

Chemical reactivity

Initially, noble gases were thought to have no reactivity due to their complete electron shells. This meant they did not need to gain or lose electrons, making it unlikely for them to form chemical bonds. However, researchers found that under conditions of extreme energy or pressure, these gases could indeed form compounds. For example:

• Xenon can form compounds when combined with fluorine.
• These reactions require special conditions, like high pressures or temperatures.

This understanding opened new possibilities in the study of chemistry and led to the shift from calling them "inert" to "noble."

Xenon hexafluoroplatinate

Xenon hexafluoroplatinate was a groundbreaking discovery in 1962 by Neil Bartlett. This compound was created by reacting xenon, a noble gas, with platinum hexafluoride. This was significant because it showed that noble gases could indeed form stable compounds. Before this, noble gases were believed to be entirely nonreactive. This compound paved the way for more studies and discoveries involving noble gas chemistry. Now, xenon is known to form a variety of other compounds, demonstrating its potential reactivity when specific conditions are met.

Neil Bartlett

Neil Bartlett was the British chemist who transformed our understanding of noble gases. In 1962, he was responsible for synthesizing xenon hexafluoroplatinate. His work challenged the belief that noble gases could not form compounds. Bartlett's experiment used xenon because it was the heaviest noble gas available, and his success led scientists to explore and redefine the capabilities of noble gases. His contribution has left a profound impact on modern chemistry, influencing how we understand chemical bonding and reactivity of elements we once considered completely inert.