ELECTRON CONFIGURATION!!

-the elctronic configuration of an atom is notation that describes the orbitals in which the electrons occupy and the total number of electrons in eaqch orbital.

-when an electron absorbs or emits a specific amount of energy it instantaneously moves from one orbital to another.

-an energy level is the amount of energy, which an electron in an atom can possess.

-energy difference between two energy level is quantom of energy.

Ground State: when all the electrons of an atom are in their lowest possible energy level.

Excited State: when one or more of an atom's electrons are in higher energy level than the lowest electron.

Orbital: an orbital is the actual region of space occupied by an electron in a particular energy level.

Shell: a shell is the set of all orbitals having the same n-value.

Subshell: a subshell is the set of orbitals of the same type.

The letters s, p, d, f refer to the four different types of orbitals, each circle represents an orbital.

For a given value of "n", different types of orbitals are possible for:
n=1 only the s- type
n=2 s- and p- types
n=3 s- , p- and d- types
n=4 s- , p- , d- and f- types.

A maximum of 2 electrons can be placed in each orbit. (Pauli Exclusion Principle)

Writing Electronic Configuration for Neutral Atoms
-always start with the lowest energy level.
-figure out how many electrons you have, then start at the lowest (1s) and keeping adding.
-each electron has an opposite spin designated by upward and downward arrows.

ex. C has 6 electrons, 2 in the 1s, 2 in the 2s and 2 in the 2p.
notice the 2 electrons in the 2p pccupy separate suborbitals and are not paired up.
the electron configuration is 1s2 2s2 2p2.

Writing Electronic Configuration for Ions
for negative ion:
-add electron to the unfilled subshell, starting where the neutral atom left off.

for positive ion:
-start with neutral atom, remove electron from the outermost shell first.
-in both s- and p- , remove from p-, first.

Core Notation
the set of electrons for an atom can be divided into two subsets: the core electrons and the outer electron.
-the core of an atom is the set of electron with the configuration of the nearest noble gas that comes before it.
-the outer electron consist of all electron outside the core electron normally take part in chemcal reactions.

locate the atom and note the noble gas at the end of the row ABOVE the element.

ex. S: 1s2 2s2 2p6 3s2 3p4
          [NE] 3s2 3p4