Chemistry Reference
In-Depth Information
Snapshot Review
❒
Atoms in a given periodic group have similar outermost electronic
configurations.
❒
The periodic table results from the electronic configurations of the
atoms, and so it can be used as a memory device to deduce these
configurations.
A. Deduce the outermost electronic configuration of Lr without bothering to
assign the inner 86 electrons to subshells.
Key Terms
Key terms are defined in the Glossary.
angular momentum quantum
number (4.3)
Bohr theory (4.2)
build-up principle (4.4)
degenerate (4.4)
discrete energy levels (4.2)
electromagnetic spectrum (4.1)
electronic configuration (4.5)
energy level diagram (4.7)
excited state (4.3)
frequency (4.1)
ground state (4.3)
Heisenberg uncertainty principle (4.6)
Hund's rule (4.7)
light (4.1)
light absorption (4.2)
light emission (4.2)
lobe (4.6)
magnetic properties (4.7)
magnetic quantum number (4.3)
rule (4.4)
orbit (4.2)
orbital (4.5)
orbital shape (4.6)
Pauli exclusion principle (4.3)
periodicity of electronic
configuration (4.8)
photon (4.1)
principal quantum number (4.3)
quantum numbers (4.3)
shell (4.5)
spin quantum number (4.3)
subshell (4.5)
wavelength (4.1)
n
/
Symbols/Abbreviations
c
(velocity of light) (4.1)
d
(a subshell) (4.5)
f
(a subshell) (4.5)
(angular momentum quantum
number) (4.3)
l
(
lambda,
wavelength) (4.1)
(magnetic quantum number) (4.3)
(spin quantum number) (4.3)
n
(principal quantum number) (4.3)
v
(
nu,
frequency) (4.1)
p
(a subshell) (4.5)
s
(a subshell) (4.5)
m
/
m
s
/
Summary
T
he chemical properties of atoms depend on their elec-
tronic structures. The number of electrons in a neutral
atom is equal to the number of protons in the nucleus—
the atomic number of the element.
Light is electromagnetic radiation that has properties
of both wave motion and a stream of particles (photons).
The wavelength of light (as a wave) is inversely propor-
tional to the energy of its photons (particles). (Section 4.1)
Bohr first proposed the concept that electrons are
arranged in discrete energy levels in the atom, which ex-
plained the emission of specific energies of light when
gaseous atoms are heated. Although Bohr's theory could
not explain many other details of the behavior of atoms, it
was a milestone in relating electronic structure and prop-
erties of atoms. (Section 4.2)
The modern theory of electronic structure is based on
the assignment of four quantum numbers to each electron
in an atom. The principal quantum number,
n,
governs the
energy of the electron and also its probable distance from
the nucleus. The angular momentum quantum number,
also has an effect on the energy and determines the shape
of the volume of space that the electron can occupy. The
magnetic quantum number, determines the orienta-
tion in space of the volume occupied by the electron, and
/
,
m
/
,
