In what case is iron 2valent and what does the 2valence and 3 valence of iron depend on?

Iron has a variety of variable valences, and at the junior high school level, Fe only shows +2 or +3 valence.

Iron is located in the fourth period group of the periodic table and the atomic number is 26.

Iron reacts with sulfur, hydrochloric acid and copper salts (solutions) that are not very oxidizing to form +2-valent ferrous sulfide (Fes), ferrous chloride (FeCl2) and ferrous salts, respectively. If iron reacts with highly oxidizing chlorine or nitric acid (heated with dilute nitric acid or concentrated nitric acid), +3-valent ferric chloride (FeCl3) and ferric nitrate [Fe(NO3)3], respectively.

The requirements for the junior high school level are:

In the displacement reaction, it is +2 valence, Fe+S=Fes Fe+2HCl=FeCl+H2 Fe+CuSO4=Cu+FeSO4

Iron is a metal commonly found in transition elements with a wide range of uses. It has variable prices of +2 and +3. When it encounters strong oxidants (such as Cl2, Br2, sufficient dilute nitric acid, etc.), Fe3+ is generated; When it encounters weaker oxidants (S, I2, Cu2+, H+, etc.), Fe2+ is generated.

Excess Fe reacts with oxygen to form FeO. Excess iron reacts with dilute nitric acid to form Fe2+, (3Fe + 8H++2NO3 = 3Fe2++2No + 4H2O). The +3-valent compound of iron is more stable than the +2-valent compound.

At room temperature, concentrated nitric acid and concentrated sulfuric acid can passivate iron, because a dense Fe3O4 oxide film is formed, which protects the internal iron from further reaction.

To put it simply, Fe is +2 valence when reacting with other substances, and +2 valence iron is +3 valence when rereacting.

Keeping in mind that iron is 2-valent in the displacement reaction, it's fine.

In the name of: XX ferrous steel!

The 2 and 3 valences of iron depend on the strength of the oxidant. Iron meets a sufficient amount of strong oxidants to form positive trivalent iron, and when it encounters weak oxidants, it forms positive bivalent iron. Strong oxidizing agents to remember:

Cl2, Br2, O3, H2O2, HCO, concentrated sulfuric acid, nitric acid, potassium permanganate solution, etc.; Weak oxidants should be known: S, I2, HCl, dilute sulfuric acid, copper sulfate salt solution.

Iron element. Iron is a metallic element with atomic number 26 and an elemental chemical formula for iron: Fe.

Pure iron is white or silvery-white with a metallic luster. Melting point 1538, boiling point 2750, soluble in strong acid and medium strong acid, insoluble in water. Iron has 0-valent, 2-valent, 3-valent, 4-valent, 5-valent and 6-valent, of which 2-valent and 3-valent are more common, and 4-valent, 5-valent and 6-valent are rare.

Iron is widely distributed in life, and the content of the earth's crust is second only to oxygen, silicon, and aluminum, ranking fourth in the earth's crust. Pure iron is a flexible and malleable silvery-white metal, used to make the core of generators and motors, iron and its compounds are also used to make magnets, drugs, inks, pigments, abrasives, etc., is one of the "ferrous metals" in the industry.

The above content reference: Encyclopedia - Iron.

The 2 and 3 valences of iron depend on the strength of the oxidation of the substances that interact with iron.

Iron reacts with sulfur, hydrochloric acid and copper salts (solutions) that are not very oxidizing to form +2-valent ferrous sulfide (Fes), ferrous chloride (FeCl2) and ferrous salts, respectively. If iron reacts with highly oxidizing chlorine or nitric acid (heated with dilute nitric acid or concentrated nitric acid). +3-valent ferric chloride (FeCl3) and ferric nitrate [Fe(NO3)3], respectively, are generated.

Characteristics of iron: Iron is a metallic element with atomic number 26 and iron elemental chemical formula: Fe.

Pure iron is white or silvery-white with a metallic luster. Melting point 1538, boiling point 2750, soluble in strong acid and medium strong acid, insoluble in water. Iron has 0 valence, +2 valence, +3 valence and +6 valence, of which +2 and +3 valence are more common, and +6 valence is rare.

Iron is widely distributed in life, and the content of the earth's crust is second only to oxygen, silicon, and aluminum, ranking fourth in the earth's crust. Pure iron is a flexible and malleable silvery-white metal used to make the cores of generators and motors.

Iron is an indispensable trace element for the human body. Among more than a dozen essential trace elements, iron is the first in both importance and quantity. A normal adult has 3g of iron in his body, which is equivalent to the mass of a small iron nail.

Divalent iron ions are oxidized with oxidants to become trivalent iron ions, and dilute nitric acid and hydrogen peroxide are commonly used.

The +3 valence compound of iron is relatively stable, and the iron ion refers to the +3 valence ion, which is the ion obtained by the iron losing the outer electrons, and the iron atom can also lose two electrons to obtain ferrous ions, and when iron reacts with elemental sulfur, copper sulfate solution, hydrochloric acid, dilute sulfuric acid, etc., it loses two electrons.

The +3-valent compound of iron is relatively stable. Iron ions are +3 valence ions, which are ions obtained by the loss of electrons in the outer shell of iron. In addition to this, the iron atom can also lose two electrons to get ferrous ions.

When iron reacts with elemental sulfur, copper sulfate solution, hydrochloric acid, dilute sulfuric acid, etc., it loses two electrons and becomes +2 valence, and with Cl2, Br2, nitric acid and hot concentrated sulfuric acid.

When reacted, it is oxidized to Fe3+. Iron with oxygen or water vapor.

The Fe3O4 formed by the reaction is often regarded as FeO·Fe2O3 but is actually a crystal with a trans-spinel structure, which is neither a mixture nor a salt. Of these, 1 3 FE is +2 and 2 3 is +3.

The 2 and 3 valences of iron depend on the strength of the oxidation of the substances that interact with iron.

For example, iron reacts with sulfur, hydrochloric acid and copper salts (solutions) that are not very oxidizing to form 2-valent ferrous sulfide (Fes), ferrous chloride (FeCl2) and ferrous salts, respectively; If iron reacts with highly oxidizing chlorine or nitric acid (heated with dilute nitric acid or concentrated nitric acid), +3-valent ferric chloride (FeCl3) and ferric nitrate [Fe(NO3)3], respectively.

Chemical properties of iron.

Iron is an indispensable metal in the industrial sector. Iron and a small amount of carbon alloy - steel, magnetization is not easy to demagnetize, is an excellent hard magnetic material, but also an important industrial material, and also as the main raw material for artificial magnetism. Iron has a variety of allotropic forms.

Iron is a relatively reactive metal, ranking ahead of hydrogen in the metal activity order table, and its chemical properties are relatively active, so it is a good reducing agent. Iron does not burn in air, but it can burn violently in oxygen.

When iron reacts chemically, whether it shows +2 valence or +3 valence depends on the substance that interacts with ironOxidationThe strength of the weakness

For example, iron reacts with sulfur, hydrochloric acid and copper salts (solutions) that are not very oxidizing to form 2-valent ferrous sulfide (Fes), ferrous chloride (FeCl2) and ferrous salts, respectively; If the iron is highly oxidizing chlorine.

or nitric acid (dilute nitric acid or concentrated nitric acid.

heating) to generate +3-valent ferric chloride, respectively.

FeCl3) and ferric nitrate Fe(NO3)3.

Valency of iron

The valency of iron is +3, while the ferrous ion is +2, because the outermost shell is 2 electrons, so it generally shows +2 valence; The 3D subshell of the subouter shell has 5 orbitals and can hold 10 electrons, but now it has only 6 electrons.

According to the electron filling principle, it is most stable when it is fully empty, full and half full. Therefore, when encountering a stronger oxidizing agent, the iron loses 1 more 3d electron, and it shows +3 valence.

Question 1: What color is ferric iron and ferric The solution containing Fe 2+ --- light green.

The solution containing Fe 3+ --- yellow.

Solution containing Cu2+ --- blue.

If both Fe2+ and Fe3+ are present, the yellow color will mask the light green, and the solution will appear yellow. If it also contains Cu 2+, it will be green.

Question 2: What is the color of 2-valent iron ions and 3-valent iron ions Fe2+ is light green, and Fe(OH)2 is generally considered white.

Fe3+ varies from light yellow to dark yellow and even brownish yellow depending on the concentration, the higher the concentration, the darker the color, and this is actually the result of the hydrolysis of iron ions.

The true hydrated iron ion [Fe(H2O)6]3+ is light purple, and the solution of iron salt can be seen in the case of strong acidity and no Cl- combination. But don't shout this in middle and high school! Don't blame me for not reminding you, whether you want to divide or the truth, you weigh it yourself.

Question 3: What are the colors of ferric iron and ferric iron? 2-valent iron: grayish-black.

3-valent iron: yellowish-brown.

Question 4: What color is the divalent iron ion green.

Question 5: What color is 3-valent iron and what color is 2-valent iron 30 points Consider Fe2+ to be light green. Fe3+ is brownish-yellow.

However, the reality is more complicated.

A: The color is different depending on the concentration.

For example, the aqueous solution of dilute Fe3+ shows light yellow, while the aqueous solution of Fe3+ with a large concentration of Fe3+ shows a dark brownish yellow, a little brownish-red, like the color of concentrated bromine water. Some even crown it with a tawny color. That's all there is to it.

B: The anions are different, and the color is also different, just like the CuSO4 solution is blue, but the newly made CuCl2 is blue-green, and the color of the silver will become the same as the blue of CuSO4 for a period of time. CU(NO3)2 is also blue, but its blue feel is a little different from the first two.

Question 6: The color of positive divalent iron Normally, the solution of divalent iron ions is light green. However, it is necessary to consider the presence or absence of other colored ions, for example, if there are Cu ions, it is possible that the green color is not obvious because the blue is very dark.

Dilute hydrochloric acid reacts with iron, and the solution is light green Copper sulfate reacts with iron, and the solution gradually turns from blue to light green.