Why is iron the most stable metal? Aren't gold and silver more stable than it?

The big explosion of the sun's death created more elements, and among these elements, the one with the most stable chemical properties as a metal is generally considered to be iridium in the platinum group.

Iridium: Atomic number 77, atomic weight 192.22, the element name comes from Latin, which means "rainbow". It was discovered in 1803 by British chemist Tennant and French chemist Descoty.

The typical characteristic of metal chemical stability is that it cannot be damaged by acid. Iridium is not only not damaged by ordinary acids, but even the king of acids, aqua regia, which is known to corrode everything, has little effect on it. Only sponge-like iridium will slowly dissolve in hot aqua regia.

Simply put, the outer electron arrangement of metal atoms is not easy to lose. The electron arrangement relationship outside the nucleus of gold atoms is 5d106s1. It has 6 electron layers, and the outermost layer has only one electron! Logically speaking, this electron should be very easy to lose! But in fact, the stability of some elements is not only affected by the outermost layer, but even the last three layers of electrons! Therefore, these are also valence electrons (valence electrons refer to electrons outside the nucleus that can interact with other atoms to form chemical bonds)! ​​Therefore, in order to change the chemical properties of gold atoms, not only the valence electrons on the sixth layer but also on the fifth layer must change! But in order to change the fifth layer of electrons in gold atoms, a lot of energy needs to be absorbed to meet the conditions! This condition cannot be achieved under most natural conditions, so the gold element is very stable!

Although the chemical properties of iron are unstable, its atomic nucleus is very stable. This is because in nature, iron mainly exists as iron-56, and the number of neutrons and protons in iron-56 are both even numbers.

In addition, the number of neutrons in iron is 30 and the number of protons is 26, which is close to one to one. Therefore, these two reasons make the iron nucleus stable.

Then there is another point. We all know that elements lighter than iron will release energy during fusion, while elements heavier than iron will release energy during fission. Whether iron is fusion or fission, it needs to absorb energy, so iron 56 is the most stable...

Iron is the sixth most abundant element in the universe. There is a reason for this. This is because iron is the end point of many stars. To put it bluntly, iron is actually a hurdle that many stars cannot overcome. Why do I say this? Why do stars have a relationship with iron?

This actually starts with the characteristics of stars. If we have to summarize the relationship between stars and elements in one sentence, it must be: stars are the alchemy furnace of elements. In the universe, hydrogen atoms account for more than 70% of the total elements in the universe, and most of the rest is helium, and less than 1% is other elements. (Here we are talking about known substances, without dark matter and dark energy)

The iron nucleus absorbs energy regardless of nuclear fission or nuclear fusion, because the iron nucleus is the most stable nucleus. The stability of the nuclear structure is determined by two forces, namely the nuclear force (strong interaction gravity) and the Coulomb force (electromagnetic force). In the nucleus, protons carry the same charge, so the Coulomb force will cause protons to repel each other. However, since there is a nuclear force between protons and neutrons, the nuclear force firmly binds protons and neutrons together like glue to prevent protons from repelling each other and separating, thus causing the nucleus to disintegrate. This is why neutrons must exist to form a heavy nucleus.

Although the outer electron arrangement of iron makes it easier for iron to lose electrons and form compounds with various substances. However, no matter how iron reacts, it is still iron, and this has not changed. Moreover, the nucleus of iron is smaller than that of gold, and it is just at the beginning of the endothermic nuclear fusion reaction. The electromagnetic force, strong force, and weak force in the nucleus are in the most stable equilibrium state. Therefore, it is difficult for the nucleus of iron to undergo nuclear fission. However, as the atomic number of gold increases, the mutual balance of these three forces is broken, and the electromagnetic force becomes stronger and stronger, so the stability becomes smaller and smaller, and the half-life is much smaller than that of iron. Therefore, from the perspective of element stability alone, gold is not as good as iron.

No one has ever said that iron is stable, let alone the "most stable". Iridium is generally considered to be the most chemically stable metal. Gold is the most stable of the common metals.

Regarding iron, when nuclear fusion occurs, the elements before iron release energy. The fusion of iron and elements after iron not only does not release energy, but absorbs energy. This leads to a relatively large content of iron in the universe. Iron can only be regarded as a dividing point and has nothing to do with stability.

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