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Elements of group 8

(group 8 elements and their properties)

Periodic Table of the Elements


The periodic table is defined as the table regulating all the chemical elements according to the increase of the atomic number from left to right, and from top to bottom. This organization corresponds to the increase of the atomic mass of the elements in general as well. The name of the group, and in which the valence electrons are distributed in a similar, which means that they have similar chemical behavior as well.

While the rows are called cycles in the periodic table, which indicates its number to a higher energy level could be occupied by electrons elements in which the case is alluded Gaza, and is a Russian chemist Dmitri Mendeleev Dmitry I. Mendeleyev founder of the league table according to the Royal Society of Chemistry.  

Elements of group 8

The group 8 is one of the groups of transition elements, which includes groups 3 to 12 in the periodic table, and share many physical and chemical properties, including that all transition elements except mercury have a relatively high melting and boiling degrees, and the transition elements share their shiny appearance, and tend to the formation of compounds in which a group of atoms gathers around a single metal atom, in addition to their tendency to form colored compounds, and elements with large atoms have a set of oxidation states, and the eighth group includes the elements of iron, ruthenium, osmium, and calcium.


Iron is known as Iron, one of the elements of the eighth group in the periodic table, which has the symbol Fe, and is the most used and cheapest metal, and iron is widely available in nature, it constitutes 5% of the earth’s crust, and is the second most abundant metal after The average amount of iron in the human body is about 4.5 grams, and about 65% of this amount in the form of hemoglobin, which transports oxygen molecules from the lungs to all parts of the body.

While It exists in various enzymes J control oxidation within cells by 1% of the total quantity in the body, and Taatkhozn most of the remaining percentage in the liver, bone marrow, spleen, Therefore, iron is an element crucial nutritional diet, which can cause deficiency anemia and fatigue that affects According to the Center for Disease Control and Prevention (CDC), pregnant women with iron deficiency are more likely to have small-sized babies early on.

Iron is the most refined metal by 90% according to the Royal Society of Chemistry, where most of the refining processes in the manufacture of steel, which is the mixture of iron and carbon used in industry and civil engineering as the manufacture of reinforced concrete.

  • The atomic number of iron is 26, and its atomic weight is 55.845.
  • The density of iron is 7.874 g / cm³. Iron is solid at room temperature, with a melting point of 1538 ° C and a boiling point of 2861 ° C.
  • There are 33 isotopes of iron, 4 of which are stable.
  • The most common isotope of iron is Hadid-56, with a natural abundance of 91.754%.


Ruthenium is a white, solid transition metal, which possesses the symbol Ru, thanks to its discovery by Karl Ernst Klaus in 1844. Ruthenium is found in nature in mineral deposits in the Urals, South and North America, as well as Peroxinite deposits in South Africa, which may be isolated for commercial use by a complex chemical process, and this element is used in many areas such as use as a multi-faceted catalyst and uses, and characteristics of the element ruthenium include:

  • Ruthenium has an atomic number equal to 44.
  • Ruthenium has a melting point of 2334 ° C and a boiling point of 4150 ° C. The atomic mass of Ruthenium is 101.07.
  • Ruthenium does not change at room temperature.
  • Scientists found Ruthenium eight cases of oxidation, and oxidation cases are +2, +3, and +4 most common.
  • Ruthenium tetroxide is a very toxic compound, which may explode.
  • Ruthenium compounds are very similar to cadmium compounds.


Osmium is one of the elements of the eighth group in the periodic table, whose name is derived from the Greek word some, which means odor, and is found in the form of a shiny silver corrosion-resistant metal, which is the densest element of all elements, the density is twice the density of lead, His discovery was due to Smithson Tennant in 1803, and the osmium has a few uses, including its use as a catalyst in the chemical industry .

  • The osmium element code is Os.
  • The atomic number of osmium is 76.
  • The boiling point of osmium is 5008 ° C and its melting point is 3033 ° C.
  • Osmium has a density of 22.5872 g / cm and a relative atomic mass of 190.23.
  • Osmium has no known vital role, but its oxide is highly volatile and toxic, causing damage to the lungs, eyes, and skin.


Hassium is a highly radioactive metal, which has the symbol Hs, and atomic number 108. Not naturally, it is produced through the extrusion of lead with iron atoms, and its discovery goes back to a team headed by Peter Armbruster and Gottfried Münzenberg in Germany. , Given the name relative to Hessen, the German state where the team’s institute is located and is currently used for research purposes only.

Presence of the elements of Main Group 8:

Inert air is 1% of the total volume of its gases. Argon gas occupies the largest share of this volume, accounting for 0.93% of the air, and the remaining 0.08% is distributed to the rest of the inert gas. Helium gas is also found in many radioactive minerals, whose nuclei result from the fragmentation of alpha particles that convert to helium gas by absorbing two electrons. Neon gas is mixed with some mineral water.

Characteristics of Main Group 8

The table shows the properties of the elements of the eighth main group by increasing the atomic number from top to bottom.
In general, the most important general characteristics of the elements of this group can be discussed as follows:

Physical properties of group 8

All inert gases are colorless and odorless. They are mono-atoms at room temperature and are difficult to liquefy due to their low critical temperatures. These gases dissolve in water. For example, argon solubility in water exceeds the solubility of oxygen.
Note :
Single-charged positive ions are formed when the metal atoms in the first group (IA) lose one electron, and the two-charged positive ions when the metal atoms in the second group (IIA) lose two electrons from their outer plane, the metals of the third group (IIIA) are positive ions. Triple charge.

However, for non-metallic elements in Group G, negative ions are single-charged by the loss of one electron in their outer plane, and non-metallic elements in the sixth group can acquire two electrons to form two-charged negative ions.

The electronic components of the wave ions are similar to the electronic components of the inert gas that precedes it in the cycle, while the negative ions, the electronic component is similar to the inert gas composition at the end of the cycle.

First ionization energy:

How does the first ionization energy of the elements of this group?

The first ionization energy decreases as the atomic number of elements of the group increases.

What is the relationship of the first ionization energy of the elements of this group and its chemical activity?

The chemical activity decreases from top to bottom of the group by increasing ionization energy

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