CH110B

Chapter 8 Notes

The Schrodinger equation cannot be solved for multielectron atoms....we must assume the orbitals are all hydrogen-like

There are some differences:

In the H atom, all subshells (s,p,d,f) of a principal shell (n) are at the same energy, but vary for other elements, though all orbitals within a subshell are at the same energy (degenerate orbitals).

Orbital energies are lower in multielectron atoms than H. (see Fig. 8.1)

In multielectron atoms, in higher numbered principal shells, some subshells have nearly identical energies.

REMEMBER, orbitals are REGIONS OF PROBABILITY

spdf notation

Numbers denote principal shell

Letters denote subshell

Superscripts denote number of electrons per subshell

Electrons occupy orbitals of the lowest energy available.

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

To remember the above, use Fig. 8.2, or BETTER YET, use the periodic table (Fig. 8.3, 8.6)

No two electrons can have the same set of 4 quantum numbers, thus an orbital can accomodate at most 2 electrons (the Pauli exclusion principle, Wolfgang Pauli 1926)

Electrons enter empty orbitals whenever possible when faced with a set of identical-energy orbitals (Hund's rule)

Electrons in half-filled orbitals have the same (parallel) spins

Thus, when drawing ground state electron configurations, the aufbau (German for "building up") principle is employed

EXCEPTIONS to aufbau:

Cr, Cu are examples where the observed configuration is not as expected due to a hyperstability of a FILLED or HALF-FILLED orbital

The outermost shell of electrons is known as the valence shell. The inner electrons are the core electrons

When writing the configuration of ions, add or remove electrons to the valence shell (often resulting in a noble gas configuration), EXCEPT for transition elements, where the outer s electrons are lost first

If two species have the same number of electrons, they are said to be isoelectronic

Magnetism

Magnetic properties result from unpaired electrons

Diamagnetic atoms have all electrons paired

Paramagnetic atoms have some unpaired electrons

Despite the fact that your instructor's thesis centered on this topic, we will not discuss it further

Periodic properties

Atomic radii (Fig. 8.9) and effective nuclear charge (Fig. 8.10), and covalent radii (Fig. 8.8)

Ionic radii (Fig. 8.12, 8.13)

Ionization energy (Fig. 8.15)

Electron affinity (Summary on Fig. 8.17)

Metallic character

Flame color

Oxidizing and reducing power

Acidic and basic character

Next week, BONDING!!!!!