Phosphorus: Element Overview

Basic Information

• Symbol: P
• Atomic Number: 15
• Atomic Weight: 30.973761998 u
• Element Category: Nonmetal
• Group: 15 (Pnictogens)
• Period: 3

Physical Properties

• Phase at Room Temperature: Solid
• Allotropes: White phosphorus, red phosphorus, black phosphorus
• Melting Point:
  • White phosphorus: 44.1 °C (111.4 °F)
  • Red phosphorus: Sublimates at 416 °C (780.8 °F)
• Boiling Point:
  • White phosphorus: 280.5 °C (536.9 °F)
  • Red phosphorus: Sublimates without boiling
• Density:
  • White phosphorus: 1.82 g/cm³
  • Red phosphorus: 2.34 g/cm³
• Color:
  • White phosphorus: Waxy white, glows in the dark
  • Red phosphorus: Red-brown powder
  • Black phosphorus: Black, shiny crystals

Chemical Properties

• Electronegativity: 2.19 (Pauling scale)
• Ionization Energies:
  • First: 1011.8 kJ/mol
  • Second: 1907 kJ/mol
  • Third: 2914.1 kJ/mol

Isotopes

• Stable Isotopes: Phosphorus has one stable isotope: P-31.
• Radioisotopes: Several, including P-32, used in biological research and medical applications.

Occurrence and Production

• Natural Abundance: Phosphorus is the 11th most abundant element in the Earth’s crust.
• Sources: Found in phosphate rocks such as apatite.
• Production: Primarily produced by heating phosphate rock in the presence of carbon and silica in an electric furnace.

Uses and Applications

• Fertilizers: Phosphorus is a key component of agricultural fertilizers.
• Detergents: Used in the manufacture of phosphates for detergents.
• Food Industry: Used as food additives and preservatives.
• Matches: Red phosphorus is used in safety matches.
• Metallurgy: Used in the production of phosphor bronze.
• Military: White phosphorus is used in incendiary devices and smoke screens.

Safety and Precautions

• Reactivity: White phosphorus is highly reactive and can ignite spontaneously in air.
• Handling: Must be stored under water or in inert atmospheres to prevent oxidation.
• Toxicity: White phosphorus is highly toxic and can cause severe burns. Red and black phosphorus are less toxic but still require careful handling.
• Environmental Impact: Excessive use of phosphorus in agriculture can lead to water pollution and eutrophication.

Biological Role

• Essential Element: Phosphorus is vital for all living organisms.
• Role in DNA/RNA: Part of the backbone of DNA and RNA.
• Energy Transfer: Integral component of ATP, the energy currency of cells.
• Cell Membranes: Forms phospholipids, essential for cell membrane structure.

Historical Background

• Discovery: Discovered by Hennig Brand in 1669 by heating urine residues.
• Naming: The name “phosphorus” comes from the Greek word “phosphoros,” meaning “light-bearer,” due to its property of glowing in the dark.

Interesting Facts

• Glowing Property: White phosphorus glows with a faint greenish light due to chemiluminescence.
• Allotropes: The different allotropes of phosphorus have distinct properties and uses.
• Bone Health: Phosphorus is essential for bone and teeth formation in humans.

Summary

Phosphorus is a versatile and essential nonmetal with several allotropes, each having unique properties. It plays a critical role in agriculture, industry, and biological systems. Discovered in the 17th century, phosphorus is known for its reactivity and its necessity in DNA, ATP, and cell membranes. Its applications range from fertilizers to safety matches, and its management is crucial due to its reactive nature and environmental impact.

Questions and Answers about Phosphorus:

1. Q: What is the chemical symbol for Phosphorus?

   • A: P

2. Q: What is the atomic number of Phosphorus?

   • A: 15

3. Q: What type of element is Phosphorus?

   • A: Nonmetal

4. Q: What is the atomic weight of Phosphorus?

   • A: 30.973761998 u

5. Q: What group is Phosphorus in?

   • A: Group 15 (Pnictogens)

6. Q: What period is Phosphorus in?

   • A: Period 3

7. Q: What is the phase of Phosphorus at room temperature?

   • A: Solid

8. Q: What are the allotropes of Phosphorus?

   • A: White phosphorus, red phosphorus, black phosphorus

9. Q: What is the melting point of white phosphorus?

   • A: 44.1 °C (111.4 °F)

10. Q: What is the boiling point of white phosphorus?

    • A: 280.5 °C (536.9 °F)

11. Q: What is the density of white phosphorus?

    • A: 1.82 g/cm³

12. Q: What is the color of white phosphorus?

    • A: Waxy white, glows in the dark

13. Q: What is the electronegativity of Phosphorus?

    • A: 2.19 (Pauling scale)

14. Q: What is the first ionization energy of Phosphorus?

    • A: 1011.8 kJ/mol

15. Q: How many stable isotopes does Phosphorus have?

    • A: One (P-31)

16. Q: What is the most common isotope of Phosphorus?

    • A: P-31

17. Q: How is Phosphorus commercially produced?

    • A: By heating phosphate rock in the presence of carbon and silica in an electric furnace

18. Q: What is the natural abundance of Phosphorus in the Earth’s crust?

    • A: 11th most abundant element

19. Q: What common mineral contains Phosphorus?

    • A: Apatite

20. Q: What industry uses Phosphorus extensively for fertilizers?

    • A: Agriculture

21. Q: What is one use of red phosphorus?

    • A: Safety matches

22. Q: What type of devices use white phosphorus?

    • A: Incendiary devices and smoke screens

23. Q: Why must white phosphorus be stored under water?

    • A: To prevent oxidation and spontaneous ignition

24. Q: What is the biological role of Phosphorus in DNA?

    • A: Part of the backbone of DNA and RNA

25. Q: What is the significance of Phosphorus in ATP?

    • A: Integral component of the energy currency of cells

26. Q: Who discovered Phosphorus?

    • A: Hennig Brand

27. Q: In what year was Phosphorus discovered?

    • A: 1669

28. Q: What is the origin of the name “Phosphorus”?

    • A: From the Greek word “phosphoros,” meaning “light-bearer”

29. Q: What property makes white phosphorus glow in the dark?

    • A: Chemiluminescence

30. Q: What health hazard is associated with white phosphorus?

    • A: Highly toxic and can cause severe burns

31. Q: How does excessive use of Phosphorus in agriculture impact the environment?

    • A: Leads to water pollution and eutrophication

32. Q: What is the second ionization energy of Phosphorus?

    • A: 1907 kJ/mol

33. Q: What is the third ionization energy of Phosphorus?

    • A: 2914.1 kJ/mol

34. Q: Is Phosphorus essential for bone health?

    • A: Yes, essential for bone and teeth formation

35. Q: How does Phosphorus benefit plants?

    • A: Strengthens cell walls and is a key nutrient

36. Q: What are the properties of black phosphorus?

    • A: Black, shiny crystals

37. Q: What is the density of red phosphorus?

    • A: 2.34 g/cm³

38. Q: How does Phosphorus contribute to the food industry?

    • A: Used as food additives and preservatives

39. Q: What is the environmental impact of Phosphorus mining?

    • A: Can lead to habitat destruction and pollution

40. Q: What is the use of Phosphorus in detergents?

    • A: Used in the manufacture of phosphates for detergents