Potassium electronic configuration

The alkali metals form a homogeneous group of extremely reactive elements which illustrate well the similarities and trends to be expected from the periodic classification, as discussed in Chapter 2. Their physical and chemical properties are readily interpreted in terms of their simple electronic configuration, ns, and for this reason they have been extensively studied by the full range of experimental and theoretical techniques. Compounds of sodium and potassium have been known from ancient times and both elements are essential for animal life. They are also major items of trade, commerce and chemical industry. Lithium was first recognized as a separate element at the beginning of the nineteenth eentury but did not assume major industrial importance until about 40 y ago. Rubidium and caesium are of considerable academic interest but so far have few industrial applications. Francium, the elusive element 87, has only fleeting existence in nature due to its very short radioactive half-life, and this delayed its discovery until 1939. 

Turn back to Figure 15-11, the energy level diagram of a many-electron atom, and consider the occupied orbitals of the element potassium. With 19 electrons placed, two at a time, in the orbitals of lowest energy, the electron configuration is... 

Potassium, 93 atomic radius, 399 atomic volume, 410 chemistry, 95 electron configuration, 271 heat of vaporization, 305 ionization energy, 268 properties, 94... 

We could follow the procedures just illustrated to write the electron configurations of elements 11 through 18 in which the 3s and 3p orbital are being filled. However, we will not write all of these out rather, we will summarize the electron configuration of argon, Is2 2s2 2p2 3s2 3p6, as (Ar). When this is done, the next element, potassium, has the configuration (Ar) 4s1 and that of calcium is (Ar) 4s2. The sum (n + l) is 4 for both the 3p and 4s levels, and the lower value of n is used first (3p). The next levels to be filled are those for which ( + ) = 5, and these are the 3d, 4p, and 5s. In this case, the 3d orbitals... 

The chart below shows electron configurations and partial orbital diagrams for the 18 elements of period 4. You would expect the filling pattern shown for potassium (Z = 19) through vanadium (Z = 23). However, an unexpected deviation from the pattern occurs with chromium (Z = 24). The same thing happens with copper (Z = 29). All other configurations for period 4 conform to the aufbau principle. 

The electron arrangement of potassium is given in the SQA Data Booklet as 2, 8, 8,1. In spectroscopic notation, the electronic configuration of potassium is 1s 2s 2p 3s 3p 4sL The diagram shows this information presented in orbital box notation. 

For brevity, many chemists record the electron configuration of an atom by giving only its outermost subshell, like As for potassium or 4/ for calcium. These electrons are most distant from the positive nucleus and, therefore, are most easily transferred between atoms in chemical reactions. These are the valence electrons. 

The charges on the chlorine, potassium, and calcium ions result from a strong tendency of valence electrons to adopt the stable configuration of the inert gases, with completely filled electronic shells. Notice that the 3 ions have electronic configurations identical to that of inert argon. 

What are the electron configurations of a chlorine anion, an argon atom, and a potassium cation ... 

This ion now can be reduced to one with an 18-electron configuration. When treated with a solution of potassium in liquid ammonia it forms the compounds K3Ni(CN)4 (with seventeen electrons) and eventually K4Ni(CN)4, in which the ions have apparent valencies of 1 and 0, respectively. The latter compound... 

SAMPLE SOLUTION (a) Potassium has atomic number 19, and so a potassium atom has 19 electrons. The ion K+, therefore, has 18 electrons, the same as the noble gas argon. The electron configurations of K+ and Ar are the same ... 

Potassium has an electron configuration of. All the alkali metals (Li, Na, K, Rb, Cs) are good reducing agents, because of the strong... 

COLOR CENTERS. Certain crystals, such as the alkali halides, can be colored by the introduction of excess alkali metal into the lattice, or by irradiation with x-rays, energetic electrons, etc. Thus sodium chloride acquires a yellow color and potassium chloride a blue-violet color. The absorption spectra of such crystals have definite absorption bands throughout the ultraviolet, visible and near-infrared regions. The term color center is applied to special electronic configurations in the solid. The simplest and best understood of these color centers is the F center. Color centers are basically lattice defects that absorb light. 

Look at the electron configurations of potassium and calcium, the s-block elements immediately preceding the first transition series. These atoms have 4s valence electrons, but no d electrons ... 

The alkali metals, as we have seen, are frisky little devils. If there is any doubt about this, watch potassium (K) burst into flame in the presence of air, or watch sodium (Na) react violently in water. As we learned in Chapter 4, there are some electron configurations that are very stable, mainly those having eight outermost electrons. The alkali metals have one outermost electron, which they are anxious to dispose of. These electrons are usually transferred to nonmetals, such as oxygen (O), chlorine (Cl), fluorine (F), and bromine (Br), with a release of energy that is predictable, pronounced, and unforgettable. 

This group contains the elements hydrogen (H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). Although hydrogen is a non-metal, it is placed in this group because of its electron configuration, Is1. 

From the electron configurations we can see that lithium is in the 2nd period, group 1A, and potassium is in the 4th period, group 1A. Since lithium is above potassium in the same group, the atomic radius of lithium is smaller than that of potassium but the first ionization energy is higher. 

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