Families oxygen

Trends in these NMR data clearly stand out as one proceeds down the penodic table, such as for the oxygen family fluonne signals are shifted downfield and... 

It will pay you to know (without having to look in the periodic table or tables of electron configurations) that the halogens (F, Cl, Br, I, At) all have seven valence electrons, that the oxygen family (O, S, Se, Te) all have six, that the nitrogen family (N, P, As) have five, that the carbon family (C, Si) have four, and that the boron family (B) have three It will also pay you to know that electronegativities decrease from right to left in a row, or from top to bottom in a column, in the periodic table... 

A is correct. Both A and D cannot be true, so the answer must be A or D. The trickiest part of this problem is to know that lead is comfortable at +2 and sulfur, being in the oxygen family, is comfortable at -2 thus these are their oxidation states when they are together. But when they are with oxygen, the -2 of the oxygen rules. 

Hence, the consequence of the addition of an electron (or hydrogen atom) to dioxygen is the production of finite fluxes of an entire group of reactive intermediates [including the strongest oxidant of the oxygen family, hydroxyl... 

The 03, O, and 0(1D) equations are a coupled set of partial differential equations whose time constants differ by many orders of magnitude. Such a set of equations is called a stiff system (see Box 5.1). It cannot be easily solved by simple methods, unless a timestep of the order of the smallest lifetime is used for the numerical integration. In view of this problem, it is very useful to define chemical families, whose lifetimes can be very much longer than those of the constituent members. Adding equations (5.24), (5.25), and (5.26) one obtains an equation describing the behavior of the sum of 0(3P), 0(1D), and 03, which is generally referred to as the odd oxygen family, Ox ... 

The definition of the odd oxygen family clearly produces a substantial increment in the photochemical time constant of the equation to be considered, enabling us to solve it more readily. The very fast reactions, such as... 

This analysis allows us to obtain the concentrations of the odd oxygen family, but it must also be partitioned into its constituent parts. This can be done by examining the photochemical equilibrium expressions for certain members of the family. If the family is composed of N members, we must write photochemical equilibrium expressions for the shortest lived N — 1 members of the family and use these to establish ratios between family members. Below the mesopause, the photochemical time constant for atomic oxygen is relatively short and one can assume that it is essentially in photochemical equilibrium. Similar conditions apply to the excited 0(1D) atom. Neglecting minor terms, Eq. (5.26) becomes... 

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