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Oxidation step i2. The stage is oxidized. Oxidized steps are characteristic

Place the schob correctly oxidation stage, It is necessary to trim the chotiri rules in the head.

1) In a simple speech, the steps of an oxidized element have a doorway 0. Apply: Na 0, H 0 2, P 0 4.

2) Slid memory elements, for some characteristic post-stage oxidation... The boolean stench has been rewritten in the tables.


3) Vishcha feet the oxidized element, as a rule, is ranked with the group number, in which the Danium element is located (for example, phosphorus is in the V group, the main source of phosphorus is +5). Important victories: F, O.

4) Shock steps of oxidation of other elements of the substrate on a simple rule:

In neutral molecules, the amount of oxidation stages of all elements is zero, and in ion - the charge of ion.

A number of simple butts for the designation of oxidation stages

butt 1... It is necessary to know the stage of oxidation of elements in ammonia (NH 3).

Decision... We already know (div. 2), art. OK. vodnyu dorіvnyuє +1. It was too late to know the qiu characteristic for nitrogen. Come on x - shukana steps oxidized. Warehouse is the simplest one: x + 3 (+1) = 0. The decision is obvious: x = -3. Like: N -3 H 3 +1.


butt 2... Add the stage of oxidation of all atoms in the H 2 SO 4 molecule.

Decision... The stages of oxidation with water and acidity are also of the same type: H (+1) and O (-2). Warehouse rivnyannya for the value of the level of oxidized oil: 2 (+1) + x + 4 (-2) = 0. Virishuchi dane rivnyannya, it is known: x = +6. Type: H +1 2 S +6 O -2 4.


butt 3... Protect the oxidation steps of all the elements in the Al (NO 3) 3 molecule.

Decision... The algorithm is too invisible. Before the warehouse of the "molecule" aluminum nitrate includes one atom of Al (+3), 9 atoms of acid (-2) and 3 atoms of nitrogen, the steps of oxidation which we need to count. For example: 1 (+3) +3 x + 9 (-2) = 0. For example: Al +3 (N +5 O -2 3) 3.


butt 4... First, start the oxidation stages of all atoms in ion (AsO 4) 3.

Decision... In this case, the amount of oxidized steps will be expensive, not zero, but the charge of ion, i.e., -3. Rivnyannya: x + 4 (-2) = -3. Type: As (+5), O (-2).

Robiti, as there are no stages of oxidation of two elements

And why can there be a degree of oxidation in the form of decal elements, which are similar to similar ones? If you look at the process from the point of view of mathematics, it will appear negative. liniyne rivnyannya There are two different types of change that cannot be matched with an unambiguous solution. Ale, mi virishuumo is not just a rivnyannya!

butt 5... First, the stage of oxidation of all elements in (NH 4) 2 SO 4.

Decision... The stages of oxidation with water and sourness, water and nitrogen are not. Classic butt zavdannya z two nevіdomimi! We will look at ammonium sulfate not as a single "molecule", but as a combination of two ions: NH 4 + і SO 4 2-. Charge the ions we see, in the skin of them only one atom will be replaced with an unattractive stage of oxidation. Corystyuyuchis dosvіdom, we wake up the hour before the front of the building, it is easy to know the degree of oxidation by nitrogen and sіrki. Type: (N -3 H 4 +1) 2 S +6 O 4 -2.

Viznovok: if a molecule contains a sprinkle of atoms with unprecedented stages of oxidation, try to "break" the molecule into a splinter of parts.

Yak to put the oxidation step in organic springs

butt 6... Add a stage of oxidation of all elements in CH 3 CH 2 OH.

Decision... The knowledge of oxidation stages in organics has its own specifics. Zokrema, it is necessary to know the degree of oxidation for the skin atom in carbon. Mіrkuvati can be an offensive rank. It is easy to see, for example, an atom in carbon in a warehouse of a methyl group. The Danium atom is C with 3 atoms in water and with a suspension atom in carbon. per link CH the substitution of electronic gustini in the bik of the atom in carbon is displayed (since the electronegativeness of the Z overturns EO water). Yakbi tse zm_shennya will be povnim, an atom in carbon adding a bi-charge -3.

The C atom in the warehouse of the CH 2 OH group is bound with two atoms of water (substitution of electronic gustini in bic C), one atom of acid (substitution of electronic gustini in bic O) and one atom in carbon (it is possible to rely on vidbuvatsya not). The stage of oxidation in the coal road is -2 +1 +0 = -1.

Type: З -3 H +1 3 C -1 H +1 2 O -2 H +1.

Do not hesitate to understand "valence" and "steps of oxidation"!

The stage of oxidation is often strayed from valence. Do not be robbed of any pardon. I will revise the main points of view:

  • oxidized step sign (+ abo -), valence - mute;
  • The steps of oxidation can be brought to zero at folding speech, the equality of valence to zero means, as a rule, that the atom of a given element is not connected with the other atoms (any kind of information is included and we will not be included here;
  • Oxidized steps - formally understanding, like nabuvaє real sense deprived of it in half with іonnyh calls, understanding “valence”, navpaki, most manually stasovuvati according to non-covalent knowledge.

The stage of oxidation (more precisely, the module) is often numerically high in valence, even more often the value is NOT used. For example, steps of oxidation with carbon in CO 2 door +4; valency C also available IV. And the axis in methanol (CH 3 OH), the valence in the carbon will be lost to the same level, and the oxidation step, C, is 1.

Small test on the topic "Steps of oxidation"

Turn a dough of hilin, turn it over, as you have adopted a theme. You need to adapt to five awkward meals. Success!

One of the main ones to understand in chemistry, to be widely victorious with the folded equations of oxidation-specific reactions, oxidation steps atom_v.

For practical purposes (in the case of folding oxidative-primary reactions), the charges on atoms in molecules with polar links are manually represented in the view of a number of numbers equal to such charges, such as those on atoms, such as valence electrons, or additional That is, the sound of the bully will be increased by the ones. Such values ​​of charges were called oxidation stages. The stage of oxidation of any element in a simple speech depends on the road 0.

In the molecules of folding speech, the actions of the elements depend on the permanent steps of oxidation. For a large number of elements, the characteristic change is the level of oxidation, which grows as a sign, as well as in size, in the presence of a molecule.

Often the steps of oxidized valence and development are familiar. Alle, there are half-days, in some steps of the oxidized element of not expensive valency. Yak has already been indicated, in the simple words of the steps of the oxidized element, it is preferable to zero, right from its valence. The tables show the valences and stages of oxidation of certain elements in the old days.

Atom (element) oxidation step in z'єднанні - the tse of the clearing charge, the calculations in pripushennі, so the data are stored only from the ions. When the stage of oxidation is determined, it is cleverly possible to allow the valence of the electrons in the system to go to larger electronegative atoms, and thus, the process of developing positively and negatively charging the ions. As a matter of fact, in a large number of applications, it will not be necessary to return electricity, but instead of changing the electronic bet from one atom to the other. That can be given a value: The stage of oxidation is a whole electric charge, like a wine bi on an atom, like an electronic bet, like a tie with some atoms in the background, went to a bigger electric, an electric power I think of the same atoms, there will be more between them.

When calculating the steps of oxidation, a number of simple rules are followed:

1 . The stage of oxidation of elements in simple fluxes, both monoatomic and molecular, to zero (Fe 0, O 2 0).

2 ... The stage of oxidation of an element in the view of a monoatomic ion is prior to the charge of the ion (Na +1, Ca +2, S -2).

3 ... In the case of a covalent polar link, a negative charge is carried up to a larger electronegative atom, and a positive one - to a lesser electronegative atom, and the stage of oxidation of elements takes on the offensive value:

The stage of oxidation of fluorine in the data sheets is set to -1;

Stage oxidized sourness in half-way roads -2 (); for a blame peroxide, de vona formally dorivnyu -1 (), acid fluoride, de vona dorivnyu +2 (), as well as superoxide and ozonides, in some steps of oxidation dorivnyu -1/2;

The stage of oxidized water in half-roads is +1 ( );

For the rain and rain-earth elements of the stages, oxidized roads are +1 and +2 as appropriate.

Most of the elements can exhibit changeable oxidation steps.

4 ... Algebraic sum of oxidation steps in neutral molecules is zero, in complex ion - the charge of ion.

For elements with a nonpotent level of oxidation, it is not important to calculate the value, I know the formula for spoluke and coryza, according to rule number 4. For example, it is necessary to increase the steps of oxidized phosphorus to phosphoric acid H 3 PO 4. Oscillations for acidic CO = -2, and for water CO = +1, then for zero sum of phosphorus, the steps of oxidized phosphorus are responsible for but expensive +5:

For example, in NH 4 Cl the amount of stages of oxidation of all atoms in the water is 4 × (+1), and the stage of oxidized chlorine is -1, and the stage of oxidized nitrogen is responsible for high-3. In sulfate ion SO 4 2- the amount of oxidation steps is -8, which is the reason for the oxidation steps +6, the total charge of ion is 2.

Understanding the level of oxidation for a greater sense of the mind is, for that, the real effective charge of the atom is not imagined, the process of understanding to achieve widespread vikorystvuyutsya in chemistry.

The maximum, and for non-metals and minimum levels of oxidation, the maximum periodical accumulation of the serial number in PSKhE D.I. Mendeleva, who is surrounded by the electronic budget of the atom.

element The value of the oxidation step і put on a half
F -1 (HF, KF)
O -2 (H 2 O, CaO, CO 2); -1 (H 2 O 2); +2 (OF 2)
N -3 (NH 3); -2 (N 2 H 4); -1 (NH 2 OH); +1 (N 2 O); +2 (NO); +3 (N 2 O 3, HNO 2); +4 (NO 2); +5 (N 2 O 5, HNO 3)
Cl -1 (HCl, NaCl); +1 (NaClO); +3 (NaClO 2); +5 (NaClO 3); +7 (Cl 2 O 7, NaClO 4)
Br -1 (KBr); +1 (BrF); +3 (BrF 3); +5 (KBrO 3)
I -1 (HI); +1 (ICl); +3 (ICl 3); +5 (I 2 O 5); +7 (IO 3 F, K 5 IO 6)
C -4 (CH 4); +2 (CO); +4 (CO 2, CCl 4)
Si -4 (Ca 2 Si); +2 (SiO); +4 (SiO 2, H 2 SiO 3, SiF 4)
H -1 (LiH); +1 (H 2 O, HCl)
S -2 (H 2 S, FeS); +2 (Na 2 S 2 O 3); +3 (Na 2 S 2 O 4); +4 (SO 2, Na 2 SO 3, SF 4); +6 (SO 3, H 2 SO 4, SF 6)
Se, Te -2 (H 2 Se, H 2 Te); +2 (SeCl 2, TeCl 2); +4 (SeO 2, TeO 2); +6 (H 2 SeO 4, H 2 TeO 4)
P -3 (PH 3); +1 (H 3 PO 2); +3 (H 3 PO 3); +5 (P 2 O 5, H 3 PO 4)
As, Sb -3 (GaAs, Zn 3 Sb 2); +3 (AsCl 3, Sb 2 O 3); +5 (H 3 AsO 4, SbCl 5)
Li, Na, K +1 (NaCl)
Be, Mg, Ca +2 (MgO, CaCO 3)
Al +3 (Al 2 O 3, AlCl 3)
Cr +2 (CrCl 2); +3 (Cr 2 O 3, Cr 2 (SO 4) 3); +4 (CrO 2); +6 (K 2 CrO 4, K 2 Cr 2 O 7)
Mn +2 (MnSO 4); +3 (Mn 2 (SO 4) 3); +4 (MnO 2); +6 (K 2 MnO 4); +7 (KMnO 4)
Fe +2 (FeO, FeSO 4); +3 (Fe 2 O 3, FeCl 3); +4 (Na 2 FeO 3)
Cu +1 (Cu 2 O); +2 (CuO, CuSO 4, Cu 2 (OH) 2 CO 3)
Ag +1 (AgNO 3)
Au +1 (AuCl); +3 (AuCl 3, KAuCl 4)
Zn +2 (ZnO, ZnSO 4)
Hg +1 (Hg 2 Cl 2); +2 (HgO, HgCl 2)
Sn +2 (SnO); +4 (SnO 2, SnCl 4)
Pb +2 (PbO, PbSO 4); +4 (PbO 2)

In chemical reactions, the rule of preserving the algebraic sum of the steps of oxidation of all atoms is observed. In general chemistry reactions oxidative and vital processes of guilt accurately compensate one other. Although the steps of oxidation, which meant a viscera, to reach a formal understanding, it’s stagnant in chemistry for advancing goals: in the first place, for the folding of equations for oxidative reaction the power of the elements in the z'udnan.

For bagatoh elementіv characteristic kіlka values ​​stupenіv oxidation, i, obchislivshi egostepen oxidation can peredbachiti okislyuvalno-vіdnovnі vlastivostі: yelement naybіlshoyu of negative oxidation stage Mauger tіlki vіddavati Electonics (okislyuvatisya) i Buti vіdnovlyuvachem, naybіlshoyu Positive mіroyu oxidation - tіlki priymati Electonics (vіdnovlyuvatisya) i we will oxidize, in the intermediate stages of oxidation - і oxidize, і vіdnovatysya.

Oxidation-renewal is a chain of interconnection processes. oxidized increase in the stage of oxidation of the element, and renewal - її change.

In the case of bagatories, people can see the oxidized waste of electricity, and renewal - how it comes. Tsei pidkhid, proponents by the Russian clerk Pisarzhevskiy (1916), it’s taken before the electrochemical processes on the electrodes, before the discharge (charging) of the ions and molecules.

However, the explanation of the change in the steps of oxidation as of the processes of generating and attaching electrons is not inevitably in the backward direction. Vono can be stashed to the point of forgiveness for the type

Cl - - ®Cl 0.

For changing the stage of oxidation of atoms in folding type

CrO 4 2 - ®Cr +3

Decrease in the positive step of oxidation to chromium from +6 to +3 in the form of less real increase in the positive charge (on Cr in CrO 4 2 - the real charge "+0.2 to the charge of the electron, and on Cr +3 - from +2 to +1.5 V rіznih z'єdnannyah).

The transfer of the charge from the lead to the oxidizing agent, the equal changes of the oxidation stage, is brought about with the participation of these particles, for example, ions H +:

CrO 4 2 - + 8H + + 3 ®Cr +3 + 4H 2 O.

Introduced a record to bear the title half-reactions .


Similar information.


In chemistry, the term "oxidized" and "renewal" means reactions, for which an atom or a group of atoms is consumed, or, apparently, add electronics. The stage of oxidation is attributed to one or more atoms, a numerical value that characterizes the number of overridden electrons and is shown by the rank of electrons to be generated by several atoms during the reaction. The value of the value can be as simple as it can be done in a folding procedure, in the presence of atoms and molecules from them. Moreover, the atoms of these elements can be volodized by the oxidation steps. Happily, for the value of the degree of oxidation, there are awkward unambiguous rules, for the singing of oxidation, to reach the knowledge of the basics of chemistry and algebra.

crocs

Part 1

The value of the oxidation step is according to the laws of chemistry

    But start, chi є dane speech is elementary. The stage of oxidation of atoms in the chemical posture is zero. The whole rule is true both for words that are set up from outside atoms, as well as for those that are built up from two or more atomic molecules of one element.

    • For example, Al (s) і Cl 2 may have oxidized steps 0, some of the offense will endure at a chemically unconnected elementary mill.
    • Beast to respect, but the allotropic form of the S 8 serki, or octacer, is unaffected by its non-Budov type, and is also characterized by a zero oxidation step.

  1. Look at the speech from the ions. The stage of oxidation of ions in the direction of the charge. The price is fair for both the big ones, and for the quiet ones, as they enter the warehouse of the chemists' spoluks.

    • For example, the stage of the oxidized ion Cl is doorway -1.
    • The stage for the oxidation of ion Cl in the warehouse of the chemical NaCl is also expensive -1. Oskіlki ion Na, for the value, maє charge +1, mirobimo, the charge of ion Cl -1, and such a rank of the steps of the oxidized road is -1.

  2. Turn it off, so that metal can be a mother of oxidation steps. Atoms of bagatokh metal elements can be monitored at different values. For example, the charge of ions of such a metal is zalizo (Fe) 2, or +3. The charge of ions in the metal (іth stages of oxidation) can be due to the charges in іonіv of the other elements, from which the metal can be entered to the warehouse of chemistry; In the text, the charge is denoted by Roman numerals: for example, zalizo (III) oxidation step is +3.

    • Yak butt is easy to read, so take revenge on aluminum. The overhead charge for AlCl 3 is zero. Oskіlki we see, that іon Cl - may charge -1, and in the future there are 3 such ions, for the overwhelming neutrality of this speech, ion Al is responsible for the charge +3. In such a rank, in the given range of steps of oxidized aluminum, the door is +3.

  3. Stupin oxidized souring dorіvnyuє -2 (for deyakie vinyatki). Mayzhe at all types of atoms acid may have oxidation steps -2. Є kіlka vinyatkіv from the tsy rule:

    • Yakshko kissen is located in the elementary stage (O 2), the stage of oxidized roads is 0, as it is in the range of the other elementary rivers.
    • Yaksho kissen to enter the warehouse peroxide, Yogo steps oxidized road -1. Peroxide is a group of spoluk, which can take revenge on a simple kissen-kisnev link (tobto anion to peroxide O 2 -2). For example, in the storage of the H2O2 molecule (peroxide), the acid has a charge and the oxidation steps -1.
    • In case of fluorine fluorine, the oxidation steps are +2, read the rule for fluorine below.

  4. Water is characterized by the level of oxidation +1, for deyakie vinyatki. Yak and for sourness, there are also vinyats here. As a rule, the stage of oxidized water is +1 (it is not found in the elementary station H 2). However, in z'єdnannyah, called hydrides, the steps of oxidized water become -1.

    • For example, in H 2 O the oxidation steps are +1, the atom is acidic, the charge is -2, and for the overwhelming neutrality, two charges of +1 are required. Protein, in the storehouse, the sodium hydroxide steps are already -1, so as the Na ion does not carry a charge of +1, and for the overhead electroneutrality the charge of the atom is water (and the latter itself is oxidized) is responsible for -1.

  5. fluorine expect MA oxidation steps -1. As it is already indicated, the stages of oxidation of certain elements (metals, atoms in peroxide, and so far) can change in the presence of a number of factors. The stage of oxidation with fluorine, however, should be set to -1. It’s worth explaining to the fact that the element is less electrically negative - it seems that fluorine atoms are most willing to be distributed with powerful electrons and most actively attract foreign electrons. With such a rank, їх charge is lost unknowingly.

  6. The amount of oxidation steps in the additional charge. The stages of oxidation of all atoms, which are included in the chemistry, in the sum of their guilt, give a charge of the state of affairs. For example, even though it is neutral, the amount of oxidation steps of all atoms is responsible for zero; as well as a high-atomic ion with a charge of -1, the amount of stages of oxidation of the road is -1, and so far.

    • It’s a good method of converting - as the amount of oxidation steps is not suitable for the zagalny charge, it means that you have mercy.

    Part 2

    The value of the oxidation step without victorian laws of chemistry

    1. Know the atoms that do not obey the strict rules of the oxidation step. According to the definition of some elements, there are no firmly established rules for perebuvannya stage of oxidation. If the atom doesn’t fall on one rule, if you don’t know its charge (for example, the atom is included in the complex, and the charge is not specified), you can get up the steps of oxidation of such an atom by the activation method. Take a look at the charge of all the other atoms in half, and then count the steps of oxidation of a given atom from the corresponding charge.

      • For example, in the case of Na 2 SO 4, the charge of the atom of the gray (S) is unavoidable - it is only known that it is not zero, the fragments of the gray are not in the elementary station. Tse z'єdnannya є with a hardened butt for the illustration of the algebraic method of assigning the stage of oxidation.

    2. Know the level of oxidation of the other elements that enter into the day. Beyond the help of the description, the rules were based on the degree of oxidation of other atoms in the half-cycle. Do not forget about the blame for the rules in times of atoms O, H and so far.

      • For Na 2 SO 4, according to our rules, we know that the charge (and that means, the oxidation steps) of the Na ion is +1, and for the skin s atoms, it becomes -2.
    3. In the case of a day, the sum of all stages of oxidation is responsible for the extra charge. For example, since the knowledge is a diatomic ion, the amount of stages of oxidized atoms is responsible for the extra ionic charge.
    4. Even more corny in the middle of the periodical tables of Mendeleev and the nobility, then in them metal and non-metal elements are being expanded.
    5. The stage of oxidation of atoms in the elementary view is set to zero. Stage of oxidation of a single ion to the front of the charge. Elements of group 1A of Mendeleev's table, such as water, lithium, sodium, in the elementary view, there may be stages of oxidation +1; The level of oxidation of metals of group 2A, such as magnesium and calcium, in the elementary view of the road +2. Kisen and water, in the form of fallowness cheery sound, Can mother 2 important values oxidation stage.

There is a cheesy element in the background, the calculations are made, but all the calls may be of the type.

The stages of oxidation can be more positive, negative or negative, because the algebraic sum of the stages of oxidized elements in molecules is based on the number of atoms in the molecule being 0, and in ion - the charge of ion.

1. The stages of oxidation of metals in the baseline are positive.

2. The food of the steps of oxidation is related to the group number periodic systems, De is known to be a danian element (the vignat is to become: Au +3(I group), Cu +2(II), from the VIII group of oxidized steps +8 can be used only in osmіu Os and ruthenia Ru.

3. The stages of oxidation of non-metals are due to the fact that there is an atom of the origin:

  • if there is a metal atom, then the oxidation step is negative;
  • Since there is a non-metal atom, then the oxidized steps can be both positive and negative. Tse lie in the form of electronegativity of atoms of elements.

4. The negative steps of oxidized non-metals can be seen in the number 8 of the group, in which there is a whole element, so that the positive steps of oxidation are in the number of electrons on the new ball, which is the name of the group.

5. The stages of oxidation of simple words are 0, directly from that of metal, non-metal.

Elementi with non-negligible oxidation stages.

element

Oxidized steps are characteristic

vignettes

Hydride metals: LIH -1

oxidation step Name the state of charge of the particle in the popped, as the sound of the rose (ma іonnyh character).

H- Cl = H + + Cl - ,

The linkage in hydrochloric acid is covalent polar. The electronic pair is replaced by the big world in the nucleus of the atom Cl - To that, wіn bіlsh elektrootrіtsatselniy element.

How many oxidation steps are there?

electronegativity- the cost of power of atoms to attract electrical elements to themselves.

The oxidation step is applied over the element: Br 2 0 , Na 0, O +2 F 2 -1,K + Cl - etc.

Vaughn can be negative and positive.

The stage of oxidation of a simple speech (unconnected, vilny stan) is expensive to zero.

The step of oxidizing sourness at a greater level of peroxide H 2 O 2, De vona dorivnyuє -1 and s'єdnannya with fluorine - O +2 F 2 -1 , O 2 +1 F 2 -1 ).

- Oxidized step a simple monoatomic ion for a charge: Na + , Ca +2 .

Water in its own days there are steps of oxidized roads +1 Na + H - and type C +4 H 4 -1 ).

At the links "metal-non-metal" there is a negative stage of oxidation with a heavy atom, which is much more electrically sensitive (data on the electroreflectance of the guidance in the Pauling scale): H + F - , Cu + Br - , Ca +2 (NO 3 ) - etc.

The rules for the value of the oxidation step in chemistry.

vіzmemo z'єdnannya KMnO 4 , it is necessary that there are stages of oxidation at the manganese atom.

міrkuvannya:

  1. Kaliy is a metal, which is in the I group of the periodic table, in connection with it, there are only positive steps of oxidation +1.
  2. Kisen, yak vіdomo, in most of its z'єdnan there are oxidized steps -2. Tsei material is not peroxide, but that means - not a blame.
  3. Warehouse Rivnyannya:

Before +Mn X O 4 -2

hey NS- we do not know the steps of oxidized manganese.

Number of atoms of calium - 1, manganese - 1, sour - 4.

It has been brought that the molecule is electrically neutral as a whole, so that the zagalny charge is zero.

1*(+1) + 1*(X) + 4(-2) = 0,

X = +7,

This means that the step of oxidized manganese to potassium permanganate = +7.

Vіzmemo іnshy butt to oxide Fe 2 O 3.

It is necessary to take into account the stages of oxidation of the atom of the vapor.

міrkuvannya:

  1. Zalizo is a metal, kissen is a non-metal, which means that kissen itself will oxidize and a negative charge. We know that kissen is oxidized stage -2.
  2. Vazhaєmo number of atoms: zaliza - 2 atoms, sour - 3.
  3. Warehouse, de NS- stages of oxidation of a zaliz atom:

2 * (X) + 3 * (- 2) = 0,

Visnovok: the stage of oxidation in the given oxidation road is +3.

Put it on. Visually the degree of oxidation of all atoms in molecules.

1. K 2 Cr 2 O 7.

Oxidation step Up to +1, I'm sour Pro -2.

I'll look at the index: О = (- 2) × 7 = (- 14), К = (+ 1) × 2 = (+ 2).

Oscillations of the algebraic sum of the steps of oxidized elements in molecules are given by the number of atoms to 0, then the number of positive steps is oxidized to the number of negative ones. oxidation stages To + O = (- 14) + (+ 2) = (- 12).

For the third point, the chromium atom has 12 positive steps to the road, or 2 atoms in the molecule, which means for one attack atom (+12): 2 = (+ 6). as follows: Up to 2 + Cr 2 +6 O 7 -2.

2.(AsO 4) 3.

In this case, the amount of oxidized steps will be expensive, not zero, but the charge of ion, i.e., E. - 3. Warehouse level: x + 4 × (- 2)= - 3 .

as follows: (As +5 O 4 -2) 3.

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