Why corrosion occured in iron but not in gold although both are transitional elements?
Answer:
iron is much above gold in the reactivity series,hence iron will react easily and readily with water,oxygen and dilute acids and corrode.
gold is highly nonreactive and will not form oxides easily or react with water and will not dissolve in dilute acids,hence it will not corrode as easily,but after very prolonged periods of time gold will corrode slightly,this is sometimes seen with old jewelery.
Gold is much less reactive than iron, its not a question of what chemical series the element is in, its a question of its place in the reactivity series. Gold will not react with air (oxygen) no matter how hard you heat it, nor will it be attacked by acids, alkalis, it is almos totally inert
Three factors are at play in corrosion.
1. Other answers have mentioned the activity series. But this is just a restatement of your observations, not an explanation. The issue is whether or not it is thermodynamically feasible to oxidize. To know that you would need to know the reduction potential of gold ions, in comparison to iron ions. If you look those up you'll see the difference plainly. Same with platinum, palladium, mercury, nickel, and other metals that are not easily oxidized.
2. Stability of the metal lattice (mainly a kinetic factor -- how FAST it will oxidize, not whether it will or won't).
3. Protective oxide overlayers. Metals like aluminum form oxides that are epitaxial with the underlying metal substrate and therefore are not easily penetrated, so the metal oxidizes a little bit and then no more.
This answer is heretical in the physics community - for now.
The materials you cite are elements. The chemical rates of reaction, which is how readily each element combines with specific other elements, is set by their presence in our solar system. The Sun is a specific type star, expressing specific harmonics at staggeringly high frequencies.
The chemical reactions taking place within this solar system are moderated by these harmonics - and sketchy research suggests that the local planet on which the chemical reactions take place also moderates reactions differently - the rates of chemical reaction on Mercury may have been found to be different than on the Earth.
Thus, in our solar system, the Sun's harmonics interface with gold in a manner which discourages formal chemical bonding - in this case, with oxygen, while iron's atomic harmonics readily match the Sun's harmonics. More exactly, iron and oxygen when bonded are very symbiotic with the Sun's vibrational harmonics, while gold with most other elements cannot form a bond that resists these Sun's attempts to tear the molecule apart. This condition also decides the geometry of more complex molecules - how some hydrocarbons have 'right' and 'left' configurations, while others may only show up in one format.
Though your question is absolute (to oxidize, or not to oxidize - that is the question), a tour through the galaxy would reveal a wide span of chemical systems in response to the local Sun. In many cases, gold might behave more like lead, and lead would be chemically reserved, but for the vast majority of the suns you visit, the variance would simply express slight differences in chemical reaction times/rates. Since the driving force of this phenomenon is atomic mass (the ability of individual atoms to respond within an ocean of ultra high frequency grows more difficult as the molecule increases in mass), the presumption is that the farther down the periodic chart, the more variance. Hydrogen should be expected to look pretty much like hydrogen where ever you go, but there will be some solar systems where plutonium will exist for only a few seconds before coming apart (fission), while in other solar systems, plutonium might have a half-life of centuries.
Imagine sending a chemical rocket to a nearby star, only to have it explode upon arrival because the chemical harmonics are different - or to not ignite, stranding the mission.
The answers post by the user, for information only, FunQA.com does not guarantee the right.
More Questions and Answers: