Problem 108 - A Complete Resource Book in Chemistry for JEE Main

Question

The statement, which prompted Neil Bartlett to prepare the first noble gas compound was (a) \(\mathrm{O}_{2}\) molecule and Xe atom have very similar ionization energies (b) \(\mathrm{PtF}_{6}\) is a strong oxidant (c) \(\mathrm{F}_{2}\) has exceptionally low bond energy (d) Xe-F bond has high bond energy

Step-by-Step Solution

Answer

(a) \(\mathrm{O}_{2}\) molecule and Xe atom have very similar ionization energies.

Step 1: Understand the Role of Ionization Energy

Neil Bartlett's preparation of the first noble gas compound was based on the similarity in ionization energies between xenon (Xe) and other elements. Ionization energy is the energy required to remove an electron from an atom. Therefore, examining ionization energy in context with Xe is crucial.

Step 2: Analyze the Options for Context

Let's look at how each option could be related:- (a) mentions the ionization energy similarity between \(\mathrm{O}_{2}\) and Xe.- (b) talks about \(\mathrm{PtF}_{6}\) as a strong oxidant.- (c) concerns the low bond energy in \({F}_{2}\).- (d) mentions the Xe-F bond energy.Based on the historical context, the focus should be on ionization energies to understand the motivations behind Bartlett's experiment.

Step 3: Determine the Key Factor

The first noble gas compound involvement stems from the realization that \({\mathrm{O}}_{2}\) and Xe have similar ionization energies. This was crucial because if \({\mathrm{O}}_{2}\) could react in certain conditions due to its ionization energy, specializing similar conditions for Xe could perhaps produce reactive compounds.

Step 4: Select the Best Answer

Given the historical context and connection to ionization energies, option (a) is the probable statement. It's about aligning ionization energies for reactive compounds in an otherwise unreactive Xe.

Key Concepts

Ionization Energy

Ionization energy is a fundamental concept in chemistry. It defines the amount of energy required to remove an electron from an atom or ion. Generally, the higher the ionization energy, the more difficult it is to remove an electron. This concept is crucial when considering the reactivity of noble gases.

Noble gases, known for their minimal reactivity, have high ionization energies. This high energy stems from their stable electron configuration. However, when comparing the ionization energies of xenon (\[Xe\]) and oxygen (\[O_2\]), Neil Bartlett realized these energies were remarkably similar.

• Ionization energy is measured in electronvolts (eV) or kilojoules per mole (kJ/mol).
• Comparing energies can predict potential chemical reactivity.
Low ionization energy implies potential reactivity.

The insight into having similar ionization energies led to the hypothesis that, under specific conditions, xenon could form compounds, just like oxygen does. Hence, understanding ionization energy serves as a gateway to exploring unexpected chemical possibilities.

Xenon Compounds

The discovery of xenon compounds marked a turning point in chemistry. This was a breakthrough because xenon, like other noble gases, was long thought to be inert. The formation of xenon compounds challenged past beliefs and opened the door to studying noble gas chemistry.

Xenon can form several compounds, primarily with fluorine (F). For instance:

• Xenon tetrafluoride (\[XeF_4\]), where xenon bonds with four fluorine atoms.
• Xenon hexafluoride (\[XeF_6\]), showing that despite being a noble gas, xenon could achieve higher coordination numbers.

Bartlett's preparation of xenon hexafluoroplatinate (\[Xe^+[PtF_6]^-\]), was the first xenon compound synthesized. This discovery illustrated xenon's potential to form compounds under specific experimental conditions.

The ability of xenon to form these compounds was previously unattainable due to its perceived inertness. This realization opened new paths in the field of inorganic chemistry, emphasizing the importance of continuously revisiting and questioning established scientific beliefs.

Chemical Reactivity

Chemical reactivity refers to how readily a substance tends to undergo a chemical change. For noble gases, chemical reactivity is quite low due to their full valence electron shells. However, the observation that noble gases could indeed react under certain conditions redefined their chemical behavior.

Several factors influence reactivity:

• Electron configuration and stability are key. A full outer shell means less likelihood of reaction.
• Ionization energy plays a central role—lower ionization energy often enhances reactivity.

In the case of xenon, high ionization energy initially suggested non-reactivity. But the insight gained through research like Bartlett's demonstrated that using strong oxidants like platinum hexafluoride (\[PtF_6\]) could alter this behavior.

The Role of Reactivity in Scientific Discovery:

• Reactivity discoveries can lead to innovative uses for elements thought to be inert.
• Understanding changes in reactivity under novel conditions enhances the scope of applied chemistry.

Thus, considering factors that affect chemical reactivity can lead to exciting discoveries and expand the boundaries of known chemistry.