Krypton

Introduction

Krypton is an element present along with the noble gases in the periodic table with the symbol Kr. It is an important element in the p block with the atomic number 36.

The discovery of elements continued to be very important in chemistry. The extraction of argon gas from air is one of the important discoveries made by scientists. The discovery of argon made scientists think about the existence of a group of elements with similar properties as argon. They even say that some other elements may be hidden in the argon gas. Therefore, liquefaction and evaporation lead to the discovery of new elements. The discovery of this element, Krypton, was in the year 1898 by Sir William Ramsay and Morris Travers. The name Krypton is derived from the Greek word, 'Kryptos'. The meaning is hidden and is because it is hidden with argon gas.

What is Krypton ?

Krypton is an element present in the periodic table having an atomic number 36. It is a colourless gas having a close association with the properties of argon gas. It is present in the nobles’ gases group or inert gases. All the elements present in this group are less or not reactive. But to a certain extent, Krypton is reactive compared to other elements. This is because they undergo chemical reactions with Fluorine and result in the formation of Krypton fluoride. It is one of the rarest gases. The element is arranged in the p block of the periodic table in period 4 and group 18.

Characteristics

Krypton is a colourless and odourless gas three times heavier than air. It is present in the monatomic form. Some characteristics of Krypton are pointed out below.

• It is the lightest one among the noble gases and tends to form isolable chemical compounds on a macroscopic level.

• It is always one of the elements after a nuclear fission reaction.

• The solid inert gas of krypton has a face-centred cubic form.

Hi-Res Images of Chemical Elements, Krypton (36 Kr), CC BY 3.0

Isotopes

Naturally obtained krypton is a mixture of six stable isotopes. They are krypton-84, krypton-82, krypton-86, krypton-80, krypton-78, and krypton-83. krypton has several other isotopes too. Among them, about 25 isotopes are found to be radioactive. And are obtained artificially by the radioactive decay of Uranium and some other compounds. krypton-81 is the longest-lived one with 229,000 years as half-life. krypton-85 is only present after the radioactive decay of a krypton and is because of its half-life, 10.7 years. The rest of the isotopes have a half-life of fewer than 3 hours.

Physical Property

Some of the physical properties of Krypton are tabulated below.

Properties	Value
Symbol	Kr
Atomic mass	83.798
Density	0.003425 g cm-3
Boiling point	-153.415°C
Melting point	-157.37°C
Electronic configuration	[Ar] 3d104s24p6
State at 20°C	Gas
Ionization energies (1st)	1350.757 kJ mol-1
Atomic radius	2.02 Å

Chemical Reactivity

Krypton was considered to be an unreactive element for over many years. But later it has been found that compared to other noble gas elements Krypton is found to have some reactivity with the other elements. Especially with Fluorine. Krypton difluoride KrF₂is formed by the reaction of Krypton with fluorine in an electrical discharge tube. The temperature required for the formation of krypton difluoride is 183 °C. So extreme conditions are needed. The reaction is,

$$\mathrm{Kr + F_2→ Kr F_2}$$

This is the first method used for the preparation of a Krypton difluoride but now several synthesis methods are adopted for example the radiation of ultraviolet light towards Krypton and fluorine will also form Krypton difluoride. The obtained product is a crystalline solid that will decompose at room temperature. No other compound combined with fluorine is not found in the case of Krypton. So only Kr F₂ is present, and Krypton has a +2 oxidation state in this compound. It is a good oxidizing and fluorinating agent.

Natural Occurrence

Krypton is a gas relatively less abundant in the earth's atmosphere. About 1 part per million is available in the earth's atmosphere. It is obtained by simple distillation of air in the liquid state. A trace amount of Krypton is present in some minerals and meteorites.

Uses

Krypton has many uses. Some of the uses of krypton in some fields are pointed out below.

• The fluoride of krypton is used in the lasers.

• Krypton gas is a product of several nuclear reactions so it can be used for the estimation of nuclear products.

• For detecting leaks in sealed containers one of the isotopes of Krypton, Krypton-85 is used. It is done with the help of radiation created by the escaped atoms.

• In electric and fluorescent lamps Krypton is present.

• For high-speed photography, Krypton gases are used.

• For respiratory organ ventilation, Krypton-85 is used.

Applications

Krypton has found many applications in different fields. They are,

• It is helpful in the nuclear chemistry field.

• It has been found useful in optics.

• It is useful in MRI imaging.

• In Computed Tomography, this has been found in applications.

• It is useful in the medical field.

• For manufacturing nuclear weapons Krypton can be used.

Side Effects

Inhalation of Krypton gas initiates some problems even though it is an inert gas. These gases have narcotic potency; it might lead to necrosis upon exposure to a higher amount. It is also asphyxiant. The exposure to higher amounts also resulted in vomiting, dizziness, nausea, etc. Muscular coordination gets destroyed in the case of high exposure to persons. Emotional instability and mental alertness get weakened as a result of this. Krypton-85, an isotope of Krypton, is also found to cause cancer.

Conclusion

Krypton is one of the important elements present in the periodic table along with the noble gases. An atomic number of Krypton is 36 and is present in the p block elements. It is a colourless and odourless inert gas with many applications. There are many isotopes for this compound and is an important element for almost all radioactive decay processes. Krypton is naturally available in the air along with other gases. Comparative other elements of the noble gases Krypton have found it to be reactive. Krypton difluoride has been formed by the combination of Krypton and fluorine and is an important chemical.

FAQs

1. Name noble gas the compound that has been fluorinated with the help of krypton difluoride.

The fluorination of xenon with the help of Krypton difluoride will result in the formation of XeF₆. Krypton difluoride can donate F^- ions the reason for the formation of this chemical compound.

2. Does krypton cause any environmental problems?

It is generally considered non-toxic to the environment because of its inertness. But at a very low temperature, it may affect the organisms in contact with it by freezing them. But there are no significant environmental problems because of this element.

3. How is krypton extracted?

Fractional distillation can be usually employed for the extraction of Krypton from the air.

4. Does the human body need krypton?

No, the human body doesn't need krypton. It has no usefulness in our bodies.

5. Can krypton be a liquid?

Under low temperatures, Krypton is present in liquid form.