It can be seen in the Table above that there is a gradual filling of the 3d orbitals across the series … (a) Electronic configuration: The elements in the same vertical column generally have similar electronic configuration. 4d and 5d orbital’s are spatially larger than 3d orbital’s so that the presence of 2 electrons in an orbital produces less electronic repulsion . In addition, mercury forms a series of compounds in the +1 oxidation … 2. Abstract. help with quantum chemistry - physical chem? If 20g of NO react with 30g of NH3, how many moles of nitrogen are formed? It can be noted that in some of these elements, the configuration of electrons corresponds to (n-1)d 5 ns 1 or (n-1)d 10 ns 1 . As per the Aufbau principle Electronic configuration of Cu should be as follow: Cu: [Ar] 3d9 4s2. However, actual configuration is as follows: Cu: [Ar] 3d10 4s1. The spectral band for the n=1 → n=2 transition in corresponds to absorption of light with wavelength lambda = 122 nm.? Electronic configurations The electronic configurations of the valence shells of the d-block elements can be given as (n-1)d1-10 ns1-2, where (n-1) stands for the inner d orbitals (Table 1). The elements of the first transition series are those for which the 3d electron shell contains between one and nine electrons. There are two main reasons for this , 1. Compounds of 1st transition series show High spin nature , the compound of 2nd and 3rd are low spin nature . Therefore, Cr and Cu have anomalous configuration. The electronic configuration of the atoms of the first row transition elements are basically the same. So, we sum up the external configuration of first-line transition elements as 4s 2 3d n. In any case, we already know that chromium and copper don’t follow this example. Because of the presence of the 4s electrons, the 3d orbitals are less shielded than the 4p orbitals; therefore, the first regular transition series begins at this point with the element scandium, which has the electron configuration [Ar]4s 2 3d 1. Copper is included because, although its outer electronic configuration is 3d 10 4s 1, it has the 3d 9 configuration in its commonly occurring +2 oxidation state. ? All three elements in group 12 have ns 2 (n − 1)d 10 valence electron configurations; consequently, the +2 oxidation state, corresponding to losing the two ns electrons, dominates their chemistry. This is a result of very low energy distinction between the 3d shell and 4s shell. Cr = 3d 5 4s 1 and Cu = 3d 10 4s 1). But second transition series shows more exceptions (i.e. 1 st Series of Electronic Configuration. It is observed that the electron first enters in higher principal quantum number orbital (n) … First transition series shows only two exceptions (i.e. The list of the first two rows of transition elements with their corresponding electronic configurations is tabulated below. This is because fully filled orbitals are more stable. the general electronic configuration is for 1st t.s is 3d(1-10) 4s(1-2) These are the transition elements found between groups 2A and 3A of the Periodic Table.