Chem133 Chapter8

• In 1870 Mendeleev saw that arranging elements by atomic mass they exhibit a periodic recurrence of similar properties.
• Today's periodic table arranges them by atomic number.

• The spin quantum number describes the electron, rather than the orbital
• The spin number can be either ±

When orbitals of equal energy are available, the electron configuration of lowest energy has the maximum number of unpaired electrons with parallel spins.

• 1s->2s->2p->3s->3p->4s->3d->4p->5s->4d->5p->6s->4f->5d->6p->7s->5f->6d->7p
• (Go diagonally down left)

Those electrons in common with the previous noble gas.

Those in the highest energy level (highest n value.) They spend most of their time farthest from the nucleus.

• Electrons involved in bonding:
• For main group electrons they are the outer electrons.
• For transition elements, in addition to the outer ns electrons the (n-1)d electrons are also valence electrons.

• When you add an electron to a 4s² 3p³ you obtain 4s¹ 3d⁶. 
• Electrons will jump between sub-levels to fill each orbital with parallel spinning electrons.
• Ths also holds true for f orbitals.

• one-half the distance between nuclei of adjacent, individual atoms in a crystal of the element.
• Used mainly for metals.

• One-half the distance between elements which occur in molecules. 
• Used for mainly for nonmetals.
• You can use a known covalent radius to find an unknown.

• Radii increase going down a group, and decrease going across a period.
• (transition metals experience similar trends, but are extremely less profound.)

• The energy required for the complete removal of 1 mol of electrons from 1 mol of gaseous atoms or ions.
• When removing more than 1 electron: IE₁< IE₂ < IE₃ <...

• As you move down a group, IE decreases because there are more inner electrons shielding the electron being removed.
• As you move across a period, IE increases because the effective charge the electrons feel from the nucleus increases. Shielding is more dramatic from inner electrons than electrons of the same energy level.

• Energy change accompanying the addition of 1 mol of electrons to 1 mol of gaseous atoms.
• Most EA₁'s are negative because the electron is attracted to the nucleus (producing an exothermic reaction.)

Their highest energy level is filled (ns²np⁶nd¹⁰...)

They share the same electron configuration as the nearest noble gas.

If you attain an isoelectronic configuration, you can't fuck with it because it's too stable, so removing or adding electrons from a noble-gas configuration takes a ton (too much) of energy.

• When an atom loses all of its highest energy level electrons.
• SnSn⁴⁺: [Kr]5s²4d¹⁰5p²[Kr]4d¹⁰

• It leaves the ns² alone
•