Lithium ground state electronic configuration

A lithium atom has three electrons. The first two electrons fill lithium s lowest possible energy level, the 1. S orbital, and the third electron occupies the 2 5 orbital. The three representations for the ground-state electron configuration... 

Refer to the sets of quantum numbers for hydrogen and helium that you saw earlier. Then use the quantum numbers for lithium to infer why a lithium atom has the ground state electron configuration that it does. 

For a lithium atom, give (a) its ground state electron configuration (b) the electron configuration for one of its lowest energy excited states and (c) an electron configuration for a forbidden or impossible state. 

Another notation describing the ground state of helium and lithium is Is2 and 1s22s1, respectively. From this notation, we can tell quickly which orbitals accommodate the electrons and how the electron spins are related to each other. Such an assignment for the electrons is called the electronic configuration of the atom. 

Ab initio quantum-mechanical calculations have been made for the two lowest electronic states of the Li02 molecule. For isosceles triangular configurations, the 2A2 state is the ground state, with equilibrium geometry r(LiO) = 1.82 A and 0(0—Li—O) = 44.5°. The 2B2 state is predicted to lie 14 kcal mol-1 higher, with r(LiO)=1.76A and 0(0—Li—0) = 46.5°. For symmetry the 2II state bond distances were predicted, r(Li—Oj = 1.62 A and r(0—0)=1.35A. There appears to be little or no barrier between the C2v and CU forms.150 The decomposition of anhydrous lithium... 

Thus the three-electron lithium atom cannot have the electron configuration (Is) the ground state is (1s)2(2s)1. Whenp, d,... orbitals are occupied it is important to remember that 3, 5,.. m values are possible. A set of p orbitals with any n can be occupied by a maximum of six electrons, and a set of d... 

We can now predict the electron configurations and orbital diagrams for the ground state of lithium, which has three electrons, and beryllium, which has four electrons ... 

A muon has the same charge and spin as an electron, but a heavier mass. What would be the ground-state configuration of a lithium atom with two electrons and one muon ... 

The alkali metals - lithium, sodium, potassium, rubidium, caesium and francium - are members of group 1 of the periodic table, and each has a ground state valence electronic configuration ns. Discussions of these metals usually neglect the heaviest member of the group, francium. Only artificial isotopes of francium are known, the longest Uved, Fr, having n = 21.8 min. 

Let us take the lithium atom as an illustrative example. The atomic number (the number of protons or electrons in the neutral atom) of lithium is 3- Therefore the orbital electronic configuration of the ground state is (lj ) (2r)k The ground-state LSMlMs term is found as follows ... 

Admittedly the lithium atom is a very simple case. To find the term designations of the ground state and excited states for more complicated electronic structures, it helps to construct a chart of the possible Ml and Ms values. This more general procedure may be illustrated with the carbon atom. The carbon atom has six electrons. Thus the orbital configuration of the ground state must be (ls)X2.s)X2py. It remains for us to find the correct ground-state term. 

The lithium atom has one 2j valence electron. In Li, the 2s-2p energy difference is small and the cA MO of Lij undoubtedly has considerable Ip character. The two valence electrons in Lia occupy the MO, giving the ground-state configuration Consistent... 

There are two electrons to place in the MO energy-level scheme for LiH shown in Fig. 2-20. This total is arrived at by adding together the one valence electron contributed by hydrogen (Ir) and the one valence electron contributed by lithium (Ir). Both electrons are accommodated in the cr MO, giving a ground-state configuration... 

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