Electronic Configurations and the Aufbau Principle

In the case of hydrogen-like atoms we have already noted that the number of nodes of the radial functions depends on the quantum numbers (see section 6.8.1). P ,. (r) always has (n — Zj — 1) radial nodes (as many as its nonrela-tivistic limit, the radial function P , , (r), has). Qn,K, ( ) has as many nodes as F ,k, (r) for negative values of K and one additional node for positive values 

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Electron Configuration and the Aufbau Principle Abbreviated Electron Configurations... 

So how is an electron configuration written First, the number of total electrons must be determined. This is the equal to the mass number for neutral atoms. For ions, the total electron is corrected for the charge (add electrons for anions subtract electrons for cations). The electrons are added according to Hund s rule and the Aufbau principle. Figure 10.3 describes the order in which the electrons are added. Keep in mind the maximum number of electrons in each type of orbital s orbitals hold two electrons, p orbitals hold six electrons, d orbitals hold ten electrons, and f orbitals hold 14 electrons. 

Write the electron configuration of an atom by using the Pauli exclusion principle and the aufbau principle. 

HF has a total of ten electrons. Using the Pauli exclusion principle and the Aufbau principle, we fill the orbitals with electrons starting from the lowest orbital. The resulting electron configuration is... 

The Madelung Rule is also caUed the Aufbau principle (from German ""Aufbau meaning build-up, fabric, structure ). This describes electron configuration and the filling of atomic orbitals. 

Use the Pauli exclusion principle and the Aufbau principle to find the electronic configuration of an element... 

The Pauli Exclusion Principle and Electron Configurations Orbital Energies and Electron Configurations Hand s Rule and the Aufbau Principle... 

Strategy Use the general rules given and the Aufbau principle to build " the electron configuration of a calcium atom and represent it with an orbital diagram. 

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 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. 

For each of the elements below, use the aufbau principle to write the full and condensed electron configurations and draw partial orbital diagrams for the valence electrons of their atoms. You may consult the periodic table in Appendix C, or any other periodic table that omits electron configurations. 

O Use the aufbau principle to write complete and condensed electron configurations for the most common ions for the elements listed below, and explain the significance of any patterns you observe in their electronic structures. 

Use the aufbau principle to write the condensed ground state electron configurations for nitrogen, phosphorus, and arsenic. 

Watch the video clips at www.brightredbooks. net. These will help you understand how to use the Pauli exclusion principle, the aufbau principle and Hund s rule to write electronic configurations of atoms. 

Electronic configurations must fit in with the electron arrangements given in the SQA Data Booklet. Remember that the electronic configurations of Cr and Cu are exceptions to the aufbau principle. 

The electron arrangements in the SQA Data Booklet and the electronic configurations written in spectroscopic notation in the table show that chromium and copper are out of step with the aufbau principle. However, there is a special stability associated with half-filled or completely filled d orbitals. Bear this in mind when looking at the orbital box notation and you can understand why chromium is [Ar] 3d 4s and copper is [Ar] 3d 4s, rather than the [Ar] 3d 4s and [Ar] dd" 4s as you might have expected. 

With the aid of the aufbau principle and Hund s rule, we are now in position to determine the ground electronic configuration of a given octahedral complex. As shown in Fig. 8.2.1 there is only one electronic assignment for d -d3 and d8 d10 complexes, which have the ground configurations... 

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