What does it mean to only close together and not cross in chemistry ? Thank you

It is said that the valency is spoken.

Closer means: Different valence states of the same element meet. Generate a common mid-price. For example, hydrogen sulfide and sulfur dioxide.

Together, sulfur elements are formed. Negative bivalent and positive quadrivalent are together and react to zero valence. However, it cannot be said that the negative quadrivalent generates the positive quadrivalent, and the positive quadruvalent decreases to the negative bivalent, so that the cross occurs. You're better off looking at it on the number line.

Do you mean valency? NH4NO3———HNO3+N2+H2O, for example.

The so-called principle of only close and not crossover means that when redox occurs in the same element in the redox reaction, their valency is only close to each other and not crossed, if it is not like that, then the nitrogen element in the ammonium root is from -3 +5, then the nitrogen element in the nitrate can only be +5 0, so that the valency is crossed (0-+5 crossed), so that the -3 distance 0 of the nitrogen element in the ammonium root is relatively tight, and +5 is also the distance 0 is relatively tight, and finally it is centered.

I don't know if you understand!!

That is, in the redox reaction, the two reactants contain a certain element, and the valency is not the same, after the reaction, the high valency is still high, the low is still low, and the maximum extent is equal, such as H2S and H2SO4 reaction, the generation of S, SO2, H2O, S is changed from H2S, and SO2 is changed from H2SO4.

The chemical price cannot be raised at a low price more than **! **Can't drop too low! They can only be close to each other!

It means that when a redox reaction occurs, if a product with multiple valences is formed after the reaction, it follows the principle of adjacent valence and does not cross with each other. For example, H2S + H2SO4 (concentrated) = S (precipitation) + SO2 (gas) + H2O, the sulfur of hydrogen sulfide changes from -2 to 0, and the sulfur of concentrated sulfuric acid changes from +6 to +4, but not -2 to +4 and +6 to 0

That's what it means.

It refers to the redox reaction taking place.

, if the product of multiple valence states is generated after the reaction, it follows the principle of adjacent valence and does not cross with each other. For example, H2S + H2SO4 (concentrated) = S (precipitation) + SO2 (gas) + H2O, hydrogen sulfide.

The sulfur changes from -2 to 0, and the sulfur of concentrated sulfuric acid changes from +6 to +4, but not -2 to +4 and +6 to 0That's what it means.

I'm talking about the law in redox reactions:

The centering reaction refers to the redox reaction of different compounds of the same element, and the valency of that element is closer to the middle.

The disproportionation reaction is just the opposite of the centering reaction, where the valency of an element spreads out to both sides, e.g. 2Na2O2+2CO2===2Na2CO3+O2

In this reaction, the O in Na2O2 is -1 valence, and it reacts with CO2 to produce Na2CO3 with O at -2 valence and O2 with O at 0 valence

The redox reaction occurs between the same element in different valence states, and the result is that the two valence states can only be close to each other or reach the same valence state at most, and there will never be a crossover phenomenon of ** state becoming low and low price state becoming high. -- The law of centering reaction.

Valence state centering means that the valency of the ** state decreases, and the valency of the low-price state increases, but it is impossible for the low state to rise more than the original ** state valence.

In the centering reaction of the redox reaction, the change of valency of the same element moves closer to the middle and has no intersection.

The rise and fall of the valency of the same element in the chemical equation.

This is for the same element, the valency is sometimes neutralized (disproportionated), in which case the negative monovalent element cannot reduce the 3rd valence to the 1st valence and itself to the positive pentavalent. (of course, the same element).

That is to say, the original high, after the reaction valency is still relatively high (special cases are equal), such as: KCLO3 + 6HCl = 3Cl2 + KCL+3H2O The above reaction is a typical antidisproportionation reaction, and the valency is close to each other, but cross. If it is written as kclo3+5kcl+3h2so4=3cl2+3k2so4+3h2o, it will be seen more clearly.

There is no essential difference from the previous reaction.

For example, +5 and +3 can only become +4 valence, and it is impossible for +5 to become +2 and +3 to +6, which means that drawing on the number line will not form a cross.

That is, if the -1 price and the +5 price cannot become the +3 price and the +1 price respectively, then it will cross, the first will rise by 4 and the second will fall by 4. So it can't be crossed.

The high valency and the low valency are close together, but not the other way around, and do not let the low overtake the high.

For example, +5 and +3 can only become +4 valence, and it is impossible for +5 to become +2 and +3 to +6, which means that drawing on the number line will not form a cross.

It is to rely on the intermediate valence reaction, and there will be no positive and negative appearance.

That is, if the -1 price and the +5 price cannot become the +3 price and the +1 price respectively, then it will cross, the first will rise by 4 and the second will fall by 4. So it can't be crossed.

It means that there are two reactants that react with redox between the same element, such as 2H2S + SO2 = 3S + 2H2O

S-2 valence and S+4 valence, obviously the product can only be less than +4 valence and greater than -2 valence, that is, close. There will be no products greater than +4 valence or less than -2 valence, obviously the oxidation of the oxidation product cannot be greater than that of the oxidant, and the reducing property of the reduction product cannot be greater than that of the reducing agent

It means that the oxidation or reduction of the resulting substance cannot be higher than that of the reactants.

That is to say, two substances that contain the same element, but the element is in a different valence state in the two compounds, and when a centering reaction occurs, they will become the kind of substance in which the valence state is between them. It will not become the other two substances. For example:

IO3- +5I- +6 H+ —3I2 + 3H2O (iodate and iodide react under acid group culture conditions to form mono-beam iodine, that is, the elements are classified into the same valence state after the reaction).

To be honest, I didn't understand what you meant. I guess you may be asking, under certain conditions, the grinding ridge can occur from left to right, and under certain conditions, it can also occur from right to left.

It's the valency shift to the middle, and I'll draw you a diagram.

The simplest explanation is that you rank all the substances that are bored (including the same elements) according to the valency from high to low (vice versa) +6 +4 0 -2, and only close to each other is not a cross and the corresponding valence line does not intersect, otherwise it is wrong.