Construction of
an Atom Notes
Heisenberg Uncertainty Principle
States that we cannot know
the position and the speed of
a moving object
simultaneously

Due to this, we will
discuss where it is
LIKELY that we will find
an electron
Important fact about electrons…
Electrons are LAZY!
They will use as little
energy as possible.

Around the Nucleus
Around the nucleus there are
Principal Energy Levels.
The Principal Energy Levels
are made up of Sublevels.
The Sublevels are made up
of Orbitals. The Orbitals
hold the electrons.
Principal Energy Levels

We call them “n”
st
 1 energy level is n=1
nd
2
energy level is n=2
rd
 3 energy level is n=3
th
 4 energy level is n=4
 Etc.
st
1
The energy level has the
lowest of energies and is the
easiest for electrons to live
in (remember, they are
lazy!).
 But if it is full, they have to
nd
go to the 2 energy level
and so on.

Sublevels

The number of sublevels in an
energy level is equal to the
value of n.
st
 1 energy level (n=1) has 1
sublevel (1s)
 2nd energy level (n=2) has 2
sublevels (2s, 2p)
rd
3
energy level (n=3) has 3
sublevels (3s, 3p, 3d)
th
 4 energy level (n=4) has 4
sublevels (4s, 4p, 4d, 4f)
 Notice the names of the
sublevel are a number (same as
n) and a letter (which will have
to do with the orbitals)
Orbitals
All s sublevels (1s, 2s, 3s, etc),
will have 1 orbital
 All p sublevels (2p, 3p, 4p,
etc), will have 3 orbitals
 All d sublevels (3d, 4d, 5d,
etc), will have 5 orbitals
 All f sublevels (4f, 5f, 6f, etc),
will have 7 orbtials

Some info about Orbitals
s orbitals are spherically shaped
and there is only 1 type
 p orbitals are dumbbell shaped
and there are 3 types
 d orbitals are complexly shaped
and there are 5 types
 f orbitals are VERY complexly
shaped and there are 7 types

Electrons in the Orbitals
Each orbital can hold a
maximum of 2
electrons