Tag Archives: group 15

Phosphorus Facts

Phosphorus is the 15th element of the periodic table. These phosphorus facts contain chemical and physical data along with general information and history.

Element cell for Phosphorus

Phosphorus Periodic Table Cell

Basic Phosphorus Facts

Name: Phosphorus

Atomic Number: 15

Element Symbol: P

Group: 15

Period: 3

Block: p

Element Family: Nonmetal

Atomic Mass: 30.973 761 998(5)

Electron Configuration: [Ne]3s23p3 (shorthand) or 1s22s22p63s23p(full)

Discovery: Hennig Brand in 1669.

German alchemist Hennig Brand isolated phosphorus from urine. He initially called his substance “cold fire” because it glowed in the dark.

Name Origin: Phosphorus was named from the Greek word phosphoros meaning “light bringer”.


Natural phosphorus is comprised of one stable isotope: 31P. Twenty two radioactive isotopes exist ranging from 24P to 46P.

Phosphorus-30 is a stable isotope containing 16 neutrons. 100% of natural phosphorus is phosphorus-31.

Phosphorus-32 is a radioactive isotope containing 17 neutrons. Phosphorus-32 decays by β- decay into 32S with a half-life of 14.263 days. This isotope is used by biologists to tag DNA and RNA changes.

Phosphorus Allotropes (Materialscientist)

These are allotropes of phosphorus. From left to right: white (yellow), red, violet, and black metallic.

Physical Data

Phosphorus has four allotropes: white, red, violet and black.

Density: white: 1.823 g/cm3
red: 2.3 g/cm3
violet: 2.36 g/cm3
white: 1.823 g/cm3

Melting Point: 317.3 K ​(44.15°C, 111.47°F)

Boiling Point: 553.7 K ​(280.5°C, 536.9°F)

State at 20ºC: Solid

Heat of Fusion: 0.66 kJ/mol

Heat of Vaporization: 51.9 kJ/mol

Molar Heat Capacity: 23.824 J/mol·K

Phosphorus Atom

Electron shell configuration of a phosphorus atom.

Atomic Data

Atomic Radius: 1.80 Å

Covalent Radius: 1.07 Å

Van der Waals Radius:  1.80 Å

Electron Affinity: 72.037 kJ/mol

Electronegativity: 2.19

1st Ionization Energy: 1011.812 kJ/mol

2nd Ionization Energy: 1907.467 kJ/mol

3rd Ionization Energy: 2914.118 kJ/mol

4th Ionization Energy: 4963.582 kJ/mol

5th Ionization Energy: 6273.969 kJ/mol

6th Ionization Energy: 21267.395 kJ/mol

7th Ionization Energy: 25430.64 kJ/mol

8th Ionization Energy: 29871.9 kJ/mol

Oxidation States: +5, -3 (common), +4, +3, +2, +1, -1, -2 (uncommon)

Fun Phosphorus Facts

  • Phosphorus is highly reactive. It is not found free in nature.
  • White phosphorus is a waxy solid and very poisonous. The lethal dose is around 50 mg.
  • White phosphorus glows in the dark and can spontaneously combust in air.
  • Red phosphorus is found on the side of matchboxes. Red phosphorus is formed when white phosphorus is heated to 250 ºC and forms a vapor. The vapor is then collected under water.
  • Phosphorus is essential to life. Phosphates (PO4-3 ions) are a major part of each molecule of DNA and RNA. They are the P in ADP and ATP, the molecules responsible for energy transport in the cell.
  • Phosphorus is found in bones. Ashes from bone was an early source of phosphorus.
  • The second of the three numbers on fertilizer is associated with phosphorus.
  • Phosphorus is the sixth most common element in the human body.
  • Phosphorus is the seventh most common element in the Earth’s crust.
  • Early matches used white phosphorus in the match head. Workers in match factories were overexposed to phosphorus and developed a painful, debilitating deformation of the jawbone known as ‘phossy jaw’
  • The border between Bolivia and Chile was altered because of phosphorus. Chile and Peru went to war with Bolivia over access to lucrative guano islands off the coast. Guano is high in nitrogen and phosphate, and in 1879, a vital source of both elements. Ultimately, Bolivia lost the land that connected them to the Pacific Ocean.
  • Overuse of phosphorus and phosphates in the environment causes algae to bloom in rivers and lakes. The excess algae uses up all the dissolved oxygen in the water and fish (and the algae) dies.
  • Hennig Brand’s process to get phosphorus from urine was a tightly kept secret. He chose to to sell his process to other alchemists. This process became more widely known when it was sold to the French Academy of Sciences in 1737.

Learn more about elements on the periodic table.

Nitrogen Facts – Element Number 7 or N

Nitrogen is the seventh element of the periodic table. These nitrogen facts contain chemical and physical data along with general information and history.

Element cell for Nitrogen

Nitrogen Periodic Table Tile

Basic Nitrogen Facts

Name: Nitrogen

Atomic Number: 7

Element Symbol: N

Group: 15

Period: 2

Block: p

Element Family: nonmetal

Atomic Mass: [14.006 43; 14.007 28] IUPAC guidelines. For single value, use 14.0067.

Electron Configuration: [He]2s22p(shorthand) or 1s22s22p(full)

Discovery: Daniel Rutherford in 1772
Rutherford’s teacher, Scottish chemist Joseph Black was working on the chemistry of air. When he removed the oxygen by burning phosphorus. He found there was still some gas left over. This mystery was left as an exercise for his student. Rutherford continued by removing the carbon dioxide from the air and showed the remaining gas did not support life or further combustion. He discovered the remaining air was insoluble in water and alkali solutions. He called his air “noxious air”.

Name Origin: Nitrogen’s name comes from the Greek words nitron and genes meaning niter and forming respectively. In 1790, French chemist Jean-Antoine-Claude Chaptal noticed the gas was part of the substance niter (potassium nitrate). French chemist Antoine Lavoisier called the gas azote from the Greek word azotos meaning lifeless. Several countries still use the name Azote for nitrogen in general use.


Natural nitrogen is comprised of two stable isotopes: N-14 and N-15. Fourteen other isotopes have been produced under laboratory conditions ranging from N-10 to N-25.

Nitrogen-14 is a stable isotope containing 7 neutrons. 99.636% of natural nitrogen is nitrogen-14.

Nitrogen-15 is a stable isotope containing 8 neutrons. 0.364% of natural nitrogen is nitrogen-11.

Liquid Nitrogen (Cory Doctorow)

Liquid Nitrogen being poured from a dewar. Credit: Cory Doctorow

Physical Data

Density: 0.001145 g/cm3

Melting Point: 63.2 K (-210.0 ºC or -346.0 ºF)

Boiling Point: 77.355 K (-195.795 ºC or -320.431 ºF)

Triple Point: 63.151 K at 12.52 kPa

Critical Point: 126.192 K at 3.3958 MPa

State at 20ºC: Gas

Heat of Fusion: 0.72 kJ/mol for N2

Heat of Vaporization: 5.56 kJ/mol for N2

Molar Heat Capacity: 29.124 J/mol·K for N2

Nitrogen atom

Electron configuration of a nitrogen atom.

Atomic Data

Atomic Radius: 1.55 Å

Covalent Radius: 0.71 Å

Van der Waals Radius:  1.55 Å

Electron Affinity: not stable

Electronegativity: (Pauling scale): 3.04

1st Ionization Energy: 1402.328 kJ/mol

2nd Ionization Energy: 2856.092 kJ/mol

3rd Ionization Energy: 4578.156 kJ/mol

4th Ionization Energy: 7475.057 kJ/mol

5th Ionization Energy: 9444.969 kJ/mol

6th Ionization Energy: 53266.835 kJ/mol

7th Ionization Energy: 64360.16 kJ/mol

Oxidation States: +5, +3, -3 (common), +4, +2, +1, -1, -2 (uncommon)

Saturn's Moon Titan

Natural color photograph of Saturn’s largest moon, Titan. Taken by Cassini probe during Saturn flyby in 2005. Credit: NASA/JPL

Fun Nitrogen Facts

  • Nitrogen is a colorless, tasteless and odorless gas.
  • Nitrogen is not found as a single element in nature. It bonds to itself to form the diatomic compound N2.
  • Nitrogen gas makes up 78% of our atmosphere.
  • Approximately 49 million tons of nitrogen are removed from the atmosphere to produce ammonia.
  • Group 15 on the periodic table is also known as the nitrogen family. An older name for the group was pnictogens. Pnictogen is from the Greek word pnikta meaning “to choke”.
  • Nitrogen is used to protect goods from oxygen. The ‘air’ in your potato chip bag is mostly nitrogen.
  • About 3% of your body weight is nitrogen. It is also the fourth most abundant element in the human body after oxygen, carbon and hydrogen.
  • Nitrogen is a key component of amino acids. There is nitrogen in every part of your DNA.
  • Nitrogen gas is relatively inert. Soil bacteria can ‘fix’ nitrogen into forms plants use to grow.
  • Nitrogen is responsible for the vibrant orange-red, blue-green, blue-violet, and deep violet colors of the aurora.
  • Saturn’s moon Titan has a dense atmosphere comprised almost entirely of nitrogen and nitrogen compounds. The yellow-orange haze (see picture)  is caused by hydrocarbon smog suspended in the atmosphere.

Learn more about elements on the periodic table.