Argon electron configuration

EXAMPLE 1 What is the empirical formula for potassium chloride Potassium loses one electron to achieve argon s electron configuration (8e in the outside orbit) and, because of this loss, forms the K+ cation. Chlorine gains one electron to achieve the argon electron configuration and forms the chloride anion, Cl-. Since compounds must be neutral, the ratio of one potassium ion to one chloride ion is the empirical formula, KC1 (and also is the molecular formula). A note of interest KC1 is often used as a substitute for NaCl for those who cannot tolerate sodium, such as heart patients. 

There is a transfer of two electrons from the calcinm atom to the oxygen atom. Note that the resulting calcium ion (Ca ) has the argon electron configuration, the oxide ion (0 ) is isoelectronic with neon, and the componnd (CaO) is electrically neutral. 

Table 4.1. Ions with Neon and Argon Electron Configurations...

A covalent bond also occurs in Cl. In the chlorine molecule, the two chlorine atoms are attracted to the same pair of electrons. Each chlorine atom has seven valence electrons in the third energy level and requires one more electron to form an electron core with an argon electron configuration. Each chlorine atom contributes one electron to the bonded pair shared by the two atoms. The remaining six valence electrons of each chlorine atom are not involved in bonding. They are variously called nonbonding electrons, lone pair electrons, or unshared electron pairs. 

The third period begins with sodium and ends with argon The atomic number Z of sodium is 11 and so a sodium atom has 11 electrons The maximum number of electrons in the Is 2s and 2p orbitals is ten and so the eleventh electron of sodium occupies a 3s orbital The electron configuration of sodium IS 2s 2p 2p 2p is ... 

Elements at the right of the periodic table tend to gam electrons to reach the elec tron configuration of the next higher noble gas Adding an electron to chlorine for exam pie gives the anion Cl which has the same closed shell electron configuration as the noble gas argon... 

To illustrate these rules, consider the Fe2+ ion. Because the atomic number of iron is 26, this +2 ion must contain 26 — 2 = 24e. Of these electrons, the first 18 have the argon structure the remaining six are located in the 3d sublevel The abbreviated electron configuration is I... 

Strategy First (1) find the total number of electrons (Z Co = 27). Then (2) find the electron configuration the first 18 electrons form the argon core, and the remaining electrons enter the 3d sublevel. Finally (3) apply Hund s rule to obtain the orbital diagram. 

A neutral chromium atom has 24 electrons, so the corresponding Cr cation has 21 electrons. The first 18 electrons follow the usual filling order to give the argon core configuration ... 

Chlorine would have to lose seven electrons to reach an electron configuration like that of neon. But if it gained one, it would have the same stable electron configuration as argon. So that is what chlorine does. If it meets an atom with a high-energy valence electron, such as sodium, the electron migrates to the chlorine atom and forms a chloride ion ... 

By losing two electrons, calcium attains the electron configuration of argon and thereby acquires a charge of 2+. ... 

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... 

Chlorine as a free element is diatomic (Cl2) however, as an ion, it will gain one electron to become isoelectronic with argon. The electronic configuration of the chloride ion is s22s22p63s23p6. The compound thus formed, aluminum chloride, has the formula A1C13. 

Sodium loses its valence electron and its electron configuration becomes identical to that of neon Is2 2s2 2p6. Likewise, the valence shell of chlorine becomes completely filled and its electron configuration resembles that of argon. As a result, during the reaction... 

In some cases, it would be convenient to condense the electron configuration. In this condensed form, the electronic configuration of the previous noble gas forms a core represented by the atomic symbol of the element enclosed in brackets (i.e., [He] or [Ne]). The electrons added since the noble gas, follow the noble gas core. For example, cobalt can be represented as an argon core plus the 4s and 3d electrons. Thus, ls22s22p63s23p64s23d7 becomes [Ar]4s23d7. 

Use the aufbau principle to write complete electron configurations and complete orbital diagrams for atoms of the following elements sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, and argon (atomic numbers 11 through 18). 

The table shows the electronic configuration in spectroscopic and orbital box notation for the elements from scandium to zinc. [Ar] represents the electronic configuration of argon, which is Is 2s 2p 3s 3p . It is okay to use this shorthand here instead of writing out the full electron shells up to 3p. However, in the exam you should write out the spectroscopic notation for each element in full. 

Table 1.17 Electronic configuration and crystal field stabilization energies for 3d electrons in transition elements. (Ar) = argon core s 2s 2p 3s 3p. ...

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. 

Krypton is an inert gas element. Its closed-shell, stable octet electron configuration allows zero reactivity with practically any substance. Only a few types of compounds, complexes, and clathrates have been synthesized, mostly with fluorine, the most electronegative element. The most notable is krypton difluoride, KrF2 [13773-81-4], which also forms complex salts such as Kr2F3+AsFe [52721-23-0] and KrF+PtFF [52707-25-2]. These compounds are unstable at ambient conditions. Krypton also forms clathrates with phenol and hydroquinone. Such interstitial substances are thermodynamicahy unstable and have irregular stoichiometric compositions (See Argon clathrates). 

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

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