Electron Configuration and Orbitals

Transition metals

follow the filling of 4s by filling 3d in the 4th period.

Ground state

: the most stable organization is the lowest possible energy.

Angular momentum quantum number

, l: values are integers from 0 to (n- 1); defines the shape of the orbitals.

Hunds rule

: for a set of orbitals in the same sublevel, there must be one electron in each orbital before pairing and the electrons have the same spin, as much as possible.

opposite spin

An orbital can hold a maximum of two electrons and they must have .

electron configuration

Each consists of: a number denoting the energy level; a letter denoting the type of orbital; a superscript denoting the number of electrons in those orbitals.

Orbital

: describes a spatial distribution of electron density; a(n) is described by a set of three quantum numbers.

electron

Every in an atom has a unique set of quantum numbers.

Principal quantum number

, n: describes the energy level of an electron in an atom; values of n range from n= 1 (ground state) to n= infinity (the electron has separated from the atom)

Half arrows

represent the electrons.

degenerate orbitals

When filling the lowest energy is attained when the number of electrons having the same spin is maximized.

Quantum numbers

can be grouped into shells, subshells and orbitals.

Lanthanide elements

(atomic numbers 57 to 70): have electrons entering the 4f sublevel.

Electron configuration

: the way electrons are distributed in an atom.

Orbital

describes a spatial distribution of electron density; an orbital is described by a set of three quantum numbers

There are 4 quantum numbers

n, l, ml and ms

Principal quantum number, n

describes the energy level of an electron in an atom; values of n range from n=1 (ground state) to n=infinity (the electron has separated from the atom)

Angular momentum quantum number, l

values are integers from 0 to (n-1); defines the shape of the orbitals

Spin quantum number, ms

the "spin" of an electron describes its magnetic field, which affects its energy; the spin quantum number has only two allowed values, +1⁄2 and -1⁄2

Electron configuration

the way electrons are distributed in an atom

Ground state

the most stable organization is the lowest possible energy

Each electron configuration consists of

a number denoting the energy level; a letter denoting the type of orbital; a superscript denoting the number of electrons in those orbitals

Hunds rule

for a set of orbitals in the same sublevel, there must be one electron in each orbital before pairing and the electrons have the same spin, as much as possible

Lanthanide elements (atomic numbers 57 to 70)

have electrons entering the 4f sublevel

94)

have electrons entering the 5f sublevel

Main-group elements

the s and p blocks