Ground-state electronic configuration atomic

Here, the bonding between carbon atoms is briefly reviewed fuller accounts can be found in many standard chemistry textbooks, e.g., [1]. The carbon atom [ground state electronic configuration (ls )(2s 2px2py)] can form sp sp and sp hybrid bonds as a result of promotion and hybridisation. There are four equivalent 2sp hybrid orbitals that are tetrahedrally oriented about the carbon atom and can form four equivalent tetrahedral a bonds by overlap with orbitals of other atoms. An example is the molecule ethane, CjH, where a Csp -Csp (or C-C) a bond is formed between two C atoms by overlap of sp orbitals, and three Csp -Hls a bonds are formed on each C atom. Fig. 1, Al. 

Water. The oxygen-atom ground-state electron configuration is l 2s 2p with an unpaired electron in each of the AOs 2py and 2p. We thus assume that these AOs along with the hydrogen Is AOs will form electron-pair bonds. The three possible ways of pairing these four AOs to get covalent structures are shown in Hg. 15.18. 

Methane. The carbon-atom ground-state electron configuration ls 2s 2p has two unpaired electrons and would seem to indicate a valence of 2. To get the well-known tetravalence of carbon, we assume that a 2s electron is promoted to the vacant 2p orbital, giving the configuration ls 2s2p. If we then assume one bond is formed with the 2s electron and three bonds are formed with the 2p electrons, the bonds are not all equivalent as they are known to be. Hence Pauling proposed that the 2s and 2p functions be linearly combined to form hybridized sp atomic orbitals, of the form... 

In conjunction with these efforts, calculations were made to predict the chemical properties of the Superheavies so that likely ores could be chosen for investigation and separation schemes devised. Separation techniques were developed to purify and identify elements with lifetimes as short as a thousandth of a second. Models were developed to predict such aggregate properties as entropies from samples as small as 500 atoms. Ground-state electron configurations, oxidation states, ionization energies, metallic radii, ionic radii, densities, melting points. 

We would normally write the electronic ground state electron configuration of a carbon atom as ls-2s 2p-. Despite the intellectual activity that has gone into defining mythical valence states for carbon atoms in different bonding situations, no one would include a d-orbital in the description of ground state carbon. 

The lowest-energy arrangement, or ground-state electron configuration, of an atom is a listing of the orbitals occupied by its electrons. We can predict this arrangement by following three rules. 

An atom consists of a positively charged nucleus surrounded by one or more negatively charged electrons. The electronic structure of an atom can be described by a quantum mechanical wave equation, in which electrons are considered to occupy orbitals around the nucleus. Different orbitals have different energy levels and different shapes. For example, s orbitals are spherical and p orbitals are dumbbell-shaped. The ground-state electron configuration of an... 

HOWTO PREDICT THE GROUND-STATE ELECTRON CONFIGURATION OF AN ATOM... 

This procedure gives the ground-state electron configuration of an atom. Any other arrangement corresponds to an excited state of the atom. Note that we can use the structure of the periodic table to predict the electron configurations of most elements once we realize which orbitals are being filled in each block of the periodic table (see Fig. 1.44). 

EXAMPLE i.io Sample exercise Predicting the ground-state electron configuration of a heavy atom... 

Predict the ground-state electron configuration of (a) a vanadium atom and (b) a lead atom. 

We account for the ground-state electron configuration of an atom by using the building-up principle in conjunction with Fig. 1.41, the Pauli exclusion principle, and Hund s rule. 

When N valence atomic orbitals overlap, they form N molecular orbitals. The ground-state electron configuration of a molecule is deduced by using the building-up principle to accommodate all the valence electrons in the available molecular orbitals. The bond order is the net number of bonds that hold the molecule together. 

The ground-state electron configurations of diatomic molecules are deduced by forming molecular orbitals from all the valence-sbell atomic orbitals of the two atoms and adding the valence electrons to the molecular orbitals in order of increasing energy, in accord ivith the building-up principle. 

A neutral helium atom has two electrons. To write the ground-state electron configuration of He, we apply the aufbau principle. One unique set of quantum numbers is assigned to each electron, moving from the most stable orbital upward until all electrons have been assigned. The most stable orbital is always ly( = l,/ = 0, JW/ = 0 ). 

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... 

C08-0098. Write correct ground-state electron configurations for the neutral atoms with atomic numbers 9, 20, and 33. 

Which of these is the ground-state electron configuration for an atom of fluorine (atomic number = 9) ... 

Table B.l summarizes the ground-state electron configuration and formal APH indices (turn number t, angular number l-n) for each known element, together with atomic number (Z) and relative atomic mass). As shown by the asterisks in the Anal column, 20 elements exhibit anomalous electron configurations (including two that are doubly anomalous - Pd and Th), compared with idealized t/l-n APH descriptors. These are particularly concentrated in the first d-block series, as well as among the early actinides. Such anomalies are indicative of configurational near-degeneracies that may require sophisticated multi-reference approximation methods for accurate description.

Table B.l. The currently known chemical elements, showing atomic number (Z), chemical symbol, name, relative atomic mass, ground-state electron configuration, and APH indices (t = turn number l-n = angular number) asterisks (, ) symbolize anomalous (APH non-conforming) ground-state electronic configurations, which are indicative of configurational near-degeneracy...

Mixed valency of this sort is the cause of the reflective, gold colour of Nao.3W03. In this system, like the MnfTc ion described above, electrons are excited optically following photon absorption from a ground-state electronic configuration to a vacant electronic state on an adjacent ion or atom. The colour is caused by a photo-effected intervalence transition between adjacent WVI and Wv valence sites ... 

Let s look at the ground state electron configuration and orbital diagram of the beryllium atom (4Be) which is the first element in group 2A. 

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. 

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