Download Quantum Mechanical Model

Section 3: The Quantum
Mechanical Model of the Atom
Bohr's Model of the Atom (cont.)
• Bohr’s model explained the hydrogen’s
spectral lines, but failed to explain any
other element’s lines.
• The behavior of electrons is still not fully
understood, but it is known they do not move
around the nucleus in circular orbits.
The Quantum Mechanical Model of the Atom
• Louis de Broglie (1892–1987)
hypothesized that particles, including
electrons, could also have wavelike
behaviors.
The Quantum Mechanical Model of the Atom
(cont.)
• Heisenberg showed it is impossible to take
any measurement of an object without
disturbing it.
• The Heisenberg uncertainty principle states
that it is fundamentally impossible to know
precisely both the velocity and position of a
particle at the same time.
• The only quantity that can be known is the
probability for an electron to occupy a certain
region around the nucleus.
» The Heisenberg Uncertainty Principle
The Quantum Mechanical Model of the Atom
(cont.)
• Schrödinger treated electrons as waves
in a model called the quantum
mechanical model of the atom.
• Schrödinger’s equation applied equally well to
elements other than hydrogen.
The Quantum Mechanical Model of the Atom
• propeller has equal probability of being
anywhere in the blurry region, but…
•…you cannot tell its exact location at
any instant.
The Quantum Mechanical Model of the Atom
(cont.)
• The wave function predicts threedimensional regions of probability where
electrons are likely to be found.
Hydrogen Atomic Orbitals
• n specifies the atom’s major energy levels,
called the principal energy levels.
Hydrogen Atomic Orbitals (cont.)
• Energy sublevels are contained within the
principal energy levels.
Hydrogen Atomic Orbitals (cont.)
• Each energy sublevel relates to orbitals of
different shape.
Atomic Orbitals are 3-dimensional regions
with a high probability of electrons
Atomic Orbitals
There is one s orbital, which
is spherical.
There are three p orbitals, which are
dumbbell-shaped.
Atomic Orbitals
•There are five d orbitals;
• four are shaped like clover-leafs
• and one is shaped like a dumbbell with a
donut around the middle.
•5.
Atomic
Orbitals
1
There are seven f orbitals.
The numbers and kinds of atomic orbitals
depend on the energy sublevel.
The number of electrons allowed in each of the first
four energy levels are shown here.
Max # of e- = 2n2
Section 5.2 Assessment
Which atomic suborbitals have a
“dumbbell” shape?
A. s
B. f
C. p
D. d
A.
B.
C.
D.
A
B
C
D
Section 5.2 Assessment
Who proposed that particles could also
exhibit wavelike behaviors?
A. Bohr
B. Einstein
C. Rutherford
D. de Broglie
A.
B.
C.
D.
A
B
C
D