Introduction
Krypton is one of the noble gases located in group number 18 of the periodic table.
- Its atomic number is 36 whereas its atomic mass is 83.79.
- It has 36 electrons.
- Krypton has 36 protons and 48 neutrons in its nucleus.
- It is represented by the symbol “Kr”.
Naming and History
The name Krypton is derived from the Greek word “Kryptos” which means hidden.
- William Ramsay and Morris Travers
In 1898, Scottish chemist William Ramsay and his English assistant Morris Travers discovered Krypton in London. They knew that there must be another element to fill the gap in the group of noble gases.
They thought that sometimes new element hides other elements and after this, they reconsider their discovery of argon. Ramsay and Travers extracted a large volume of argon from the air and liquifies it.
Travers removed oxygen from air by red hot copper and magnesium. He then took the remaining gas and put it in a vacuum tube to measure the spectrometer by passing current. They observed it under the spectrometer and found a new element.
Occurrence of Krypton
The Krypton is a rare element. It has a very low abundance in air. Some traces are found in Earth’s crust. When uranium or other radioactive elements break down, they form krypton. The Earth’s atmosphere contains about 0.0001% krypton.
Properties of Krypton
Krypton is an inert, colorless, tasteless, and odorless gas. Solid krypton is a face-centered white crystalline structure. Although krypton is highly chemically inactive but can react with reactive fluorine to form Krypton difluoride.
Krypton has characteristic brilliant green and orange spectral lines. The melting point of krypton is -157.36°C and its boiling point is -153.22°C. It has a density of 0.003733 grams per cubic centimeter. It exists as a gas at room temperature.
Krypton in Biological System
There is no known significant role of krypton in living organisms. It is non-toxic.
Uses of Krypton
- Due to the highly expensive process of obtaining krypton from air, its practical applications are limited but some important uses are given below:
- Krypton is used in lightening products such as bulbs, lamps, projection lamps, and fluorescent tubes.
- Mixtures of argon and krypton are used in light bulbs.
- High-speed photography and some high-quality photographic flashes use krypton.
- It is used in arc lights such as in airports.
- It is also used along with other gases in neon signs to produce brilliant green light.
- From 1960 to 1983, the wavelength of krypton- 86 was used as a standard unit of length.
- Krypton ion laser is used in the research and the study of proteins.
- Krypton fluorides are used in some lasers.
Isotopes of Krypton
There occur almost 25 isotopes of krypton from mass number 71 to 95. There are six, stable naturally occurring isotopes. The most abundant one is krypton- 84 with 57 percentage.
- Krypton- 83 is used in Magnetic Resonance Imaging because of its high spin.
- The isotope krypton- 85 is used along with phosphorus to produce objects that shine in dark.
- Kr- 85 is also used to detect leaks in containers.
MCQs
- What is the atomic number of krypton?
- A) 16
- B) 26
- C) 36
- D) 46
- Answer: C) 36
- What is the atomic mass of krypton?
- A) 83.79
- B) 92.15
- C) 64.32
- D) 76.94
- Answer: A) 83.79
- Who discovered krypton, and in which year?
- A) Marie Curie in 1902
- B) William Ramsay and Morris Travers in 1898
- C) Dmitri Mendeleev in 1869
- D) Antoine Lavoisier in 1778
- Answer: B) William Ramsay and Morris Travers in 1898
- What does the name “Krypton” mean, and where does it originate from?
- A) Bright and shining
- B) Hidden
- C) Noble
- D) Luminous
- Answer: B) Hidden
- How did William Ramsay and Morris Travers discover krypton?
- A) By isolating it from water
- B) By extracting it from uranium
- C) By liquifying argon and observing a new element
- D) By synthesizing it in a laboratory
- Answer: C) By liquifying argon and observing a new element
- In which state is krypton found at room temperature?
- A) Solid
- B) Liquid
- C) Gas
- D) Plasma
- Answer: C) Gas
- What is the abundance of krypton in Earth’s atmosphere?
- A) 0.001%
- B) 0.0001%
- C) 1%
- D) 0.01%
- Answer: B) 0.0001%
- What type of structure does solid krypton have?
- A) Cubic
- B) Hexagonal
- C) Face-centered white crystalline
- D) Amorphous
- Answer: C) Face-centered white crystalline
- Which gas can krypton react with to form Krypton difluoride?
- A) Oxygen
- B) Nitrogen
- C) Helium
- D) Fluorine
- Answer: D) Fluorine
- What is the melting point of krypton?
- A) -157.36°C
- B) -273.15°C
- C) 0°C
- D) 100°C
- Answer: A) -157.36°C
- In what application is krypton used in conjunction with argon?
- A) Medical imaging
- B) Neon signs
- C) Light bulbs
- D) High-speed photography
- Answer: C) Light bulbs
- What is the primary application of krypton ion laser?
- A) Welding
- B) Cutting
- C) Medical imaging
- D) Protein research
- Answer: D) Protein research
- Which isotope of krypton is used in Magnetic Resonance Imaging?
- A) Kr-86
- B) Kr-84
- C) Kr-85
- D) Kr-83
- Answer: D) Kr-83
- What is the most abundant naturally occurring stable isotope of krypton?
- A) Kr-82
- B) Kr-84
- C) Kr-85
- D) Kr-86
- Answer: B) Kr-84
- How many naturally occurring stable isotopes does krypton have?
- A) 3
- B) 4
- C) 5
- D) 6
- Answer: D) 6
- What is the primary use of krypton-85 along with phosphorus?
- A) Medical imaging
- B) Leak detection
- C) Light bulbs
- D) Protein research
- Answer: B) Leak detection
- What does the name “Krypton” mean in Greek?
- A) Luminous
- B) Bright and shining
- C) Hidden
- D) Noble
- Answer: C) Hidden
- Who discovered krypton, and where did the discovery take place?
- A) Marie Curie in Paris
- B) William Ramsay and Morris Travers in London
- C) Dmitri Mendeleev in Moscow
- D) Antoine Lavoisier in Berlin
- Answer: B) William Ramsay and Morris Travers in London
- What is the density of krypton?
- A) 0.0012 grams per cubic centimeter
- B) 0.003733 grams per cubic centimeter
- C) 0.01 grams per cubic centimeter
- D) 0.1 grams per cubic centimeter
- Answer: B) 0.003733 grams per cubic centimeter
Summary: Krypton Element Tutorial
Krypton, a noble gas in group 18 of the periodic table, possesses an atomic number of 36 and an atomic mass of 83.79. Discovered in 1898 by William Ramsay and Morris Travers, the name “Krypton” originates from the Greek word “Kryptos,” meaning hidden.
Key Points:
- Occurrence: Krypton is a rare element with minimal abundance in the Earth’s atmosphere (0.0001%). It forms when radioactive elements, like uranium, break down.
- Properties: Krypton is an inert, colorless, tasteless, and odorless gas. In a solid state, it exhibits a face-centered white crystalline structure. Notably, it can react with reactive fluorine to form Krypton difluoride. With a melting point of -157.36°C and boiling point of -153.22°C, krypton exists as a gas at room temperature with a density of 0.003733 grams per cubic centimeter.
- Biological Significance: Krypton has no known significant role in living organisms and is non-toxic.
- Uses: Despite the expensive extraction process, krypton finds applications in:
- Lighting products such as bulbs, lamps, and fluorescent tubes.
- Mixtures with argon in light bulbs.
- High-speed photography and high-quality photographic flashes.
- Arc lights in airports.
- Neon signs to produce brilliant green light.
- Historical use from 1960 to 1983 for the wavelength of krypton-86 as a standard unit of length.
- Krypton ion laser in protein research.
- Krypton fluorides in some lasers.
- Isotopes: Krypton has approximately 25 isotopes, with six stable naturally occurring isotopes. Krypton-84 is the most abundant, comprising 57%. Specific isotopes, such as krypton-83 and krypton-85, have applications in Magnetic Resonance Imaging and leak detection, respectively.