Oxidation numbers maximum

K.22 (a) Determine and tabulate the maximum (most positive) and minimum (most negative) oxidation numbers of the elements in the first seven main groups. Hint ... 

Maximum oxidation numbers are often found in the oxoanion with the most oxygen atoms. For minimum oxidation numbers, consult Fig. C.6. (b) Describe anv patterns you see in the data. 

Chlorine can exist in both positive and negative oxidation states. What is the maximum (a) positive and (b) negative oxidation number that chlorine can have (c) Write the electron configuration for each of these states, (d) Explain how you arrived at these values. 

Group 13/III is the first group of the p block. Its members have an ns np1 electron configuration (Table 14.5), and so we expect a maximum oxidation number of +3. The oxidation numbers of B and A1 are +3 in almost all their compounds. However, the heavier elements in the group are more likely to keep their s-electrons (the inert-pair effect, Section 1.19) so the oxidation number +1 becomes increasingly important down the group, and thallium(I) compounds are as common as... 

The composition of sodium polysulfide solutions saturated with sulfur of zero oxidation number (S°) has also been studied at 25 and 80 °C (solutions in contact with elemental sulfur) [76]. In this case the ratio 8° 8 per polysulfide ion increases with increasing alkahnity. The maximum average number of sulfur atoms per polysulfide molecule was obtained as 5.4 at 25 °C and 6.0 at 80 °C and pH values of >12. Equilibrium constants for reactions as in Eqs. (26) and (27) have been derived assuming various models with differing numbers of polysulfide ions present. 

The oxidation number of oxygen in its compounds is -2 except in peroxides (where it is -1), superoxides (where it is - ), or in OF2 and 02F2 (where it is positive). The peroxides and superoxides generally occur only with other elements in their maximum oxidation states. You will be able to recognize peroxides or superoxides by the presence of pairs of oxygen atoms and by the fact that if the compounds were normal oxides, the other element present would have too high an oxidation number (Sec. 13.3). 

S is in periodic group VIA, and so its maximum oxidation number is +6 and its minimum oxidation number is 6 - 8 = -2. It also has an oxidation number of 0 when it is a free element. 

The more electronegative element will take the negative oxidation state, (a) The maximum oxidation state of sulfur is +6 the most common negative oxidation number of oxygen is -2. Therefore, it takes three oxygen atoms to balance one sulfur atom, and the formula is SO v (b) The maximum oxidation state of carbon is +4 the only oxidation number of fluorine in its compounds is - 1. Therefore, it takes four fluorine atoms to balance one carbon atom, and the formula is CF4,... 

If phosphorus pentoxide were POs, phosphorus would have an oxidation number of + 10, which exceeds its group number. The maximum oxidation number that phosphorus can have is + 5 (from group VA), and so the formula is P205. (The compound cannot be a peroxide it was named oxide. )... 

The rules above gave maximum and minimum oxidation numbers, but those might not be the only oxidation numbers or even the most important oxidation numbers for an element. Elements of the last six groups of the periodic table for example may have several oxidation numbers in their compounds, most of which vary from each other in steps of 2. For example, the major oxidation states of chlorine in its compounds are -1, +1, +3, +5, and +7. The transition metals have oxidation numbers that may vary from each other in steps of 1. The inner transition elements mostly form oxidation states of + 3, but the first part of the actinoid series acts more like transition elements and the elements have... 

Ans. If you calculate the oxidation number assuming that the oxygen atoms are normal oxide ions, you get an answer +7, which is greater than the maximum oxidation number for sulfur. That must mean that one of the pairs of oxygen atoms is a peroxide, and thus the sulfur must be in its highest oxidation number, +6. The ion is peroxydisulfate ... 

Ans. (a) Since one half-reaction is a reduction, the other half-reaction must be an oxidation. (b) The maximum oxidation state for nitrogen is +5, because nitrogen is in periodic group V. Since it starts out in oxidation number +4, it must be oxidized to +5. 

Table 4.2. Lewis-like oxidation numbers (n07L), formal d count, metal electron configuration (eep, Chp) and minimum and maximum coordination numbers (ncs) for low-spin normal-valent compounds of group 6-11 transition metals...

B) In SO3, the sulfur has a +6 oxidation number the sulfur cannot be oxidized further. The other elements bound to oxygen in the other choices have oxidation numbers less than their maximum value and can undergo further oxidation. 

The three elements to be treated in this chapter (V, Cr, Mn) are the third, fourth, and hfth members of the first transition series. The first two members (Sc, Ti) have been treated in previous chapters (Chapters 12 and 13). The ten elements of this first transition series (Sc through Zn) are characterized by electron activity in the 3d-4s levels. All elements in the 3d transition series are metals, and many of their compounds tend to be colored as a result of unpaired electrons. Most of the elements have a strong tendency to form complex ions due to participation of the d electrons in bonding. Since both the 4s and the 3d electrons are active, most of the elements show a considerable variety of oxidation states (Sc and Zn being exceptions). For the first five (Sc through Mn), the maximum oxidation number is the total number of electrons in the 4s and 3d levels. Complexing is often so strong that the most stable oxidation state for simple compounds may differ from that for complex compounds. 

Bismuth can have both positive and negative oxidation numbers. What is (a) the maximum positive value and (b) the maximum negative value that bismuth can have for a chemically realistic oxidation number ... 

What is the maximum positive oxidation number expected for each of the following elements ... 

There is a periodicity in oxidation numbers as shown in the table below for examples of oxides with the maximum oxidation number. Remember that an element may occur in different compounds in several different oxidation states. 

Oxide with maximum oxidation number Li20 BeO B2O3 C02 N2O5 CI2O7 Xe04... 

The maximum oxidation number for most elements is equal to the classical group number of the element. 

Figure 16.1 Exceptions to the Maximum Oxidation Number Rule...

The maximum oxidation number of sulfur is +6, equal to its group number. Sulfur also has the oxidation state 0 when it is not combined and a minimum oxidation state of 6 - 8 = -2. (Sulfur can also have oxidation states +4 and + 2, not covered by the rules given so far.)... 

The maximum oxidation number of sulfur, equal to its group number, is +6. Because the oxidation numbers vary mostly in steps of 2 in this portion of the periodic table, we can deduce (correctly) that sulfur also has -1-4 and +2 as oxidation numbers. Examples of compounds in which sulfur has these three oxidation numbers are SFg, SF4, and SF2. 

Chlorine in its compounds with elements other than oxygen and fluorine, exhibits a negative oxidation number, 1 (rule 8, Section 16.1). Thus, the oxidation number of carbon in this compound must be positive. The maximum oxidation number of carbon in its compounds is +4 because it is in group IV. Thus, the formula is CCI4. The sum of the four (1) oxidation numbers for the chlorine atoms and the one (+4) oxidation number for the carbon atom is zero, the charge on the compound. ... 

Oxidation number is a periodic property. For example, for most elements the maximum oxidation number is equal to the classical group number, and the minimum oxidation number for nonmetals other than hydrogen is the group number minus 8. 

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