Download Name: Date: ______ Current Atomic Models Refining Nuclear

Name: _______________________
Date: _________
Current Atomic Models
Refining Nuclear Models
• In 1913, Danish physicist, Niels Bohr, refined Rutherford's idea by adding
that the electrons were in orbits around the nucleus. Rather like planets
orbiting the sun. With each orbit only able to contain a set number of
electrons.
• He proposed a ___________________ or Orbit model
The Bohr Model
1. Electrons revolve around the nucleus in specific _____________ (shells),
or __________________________.
• 2. An atom has energy levels. Electrons can only exist in these energy levels,
not in between.
• 3. When an atom is in the ground state, the electrons exist in the energy
levels _____________________________________.
• 4. If an atom receives, energy, the atom becomes excited and electrons
_________________________________________________________.
Ground State
• The lowest energy state of an
atom
• Electrons in the first energy level
have the lowest potential energy
since they are located closest to
the nucleus.
•
Excited State
• An atom with _________________________________ than in the ground
state because electrons have “jumped” to a higher energy level.
• Electrons with higher potential energy occupy orbits farther from the
nucleus. The _____ an electron is from the nucleus, the ______ its energy!
Current Atomic Model
• Electrons act like __________ (because they have a mass) and _________
(because they have certain frequencies corresponding to their energy levels)
• Electrons are located in orbitals around the nucleus that correspond to
specific energy levels
• Electron clouds = orbitals that do not have sharp boundaries, but shows 3D
region where electrons are most probable to be found.
• ____________________ Model or ____________ Model proposed by
Louis de Broglie & Erwin Schrodinger
Electron Configuration
• Arrangement of electrons
• Each atom has a distinct ___________________________.
• The ____________________ electron configuration is found on the
periodic table in the lower left hand corner of each box.
Classify the following as ground state electron
configurations or excited state electron configurations.
Element
ground state electron configurations or
excited state electron configuration
lithium
1-2
calcium
2-8-7-3 excited
chlorine
2-8-7
ground
aluminum
2-7-4
excited
neon
2-7-1
excited
sodium
2-8-1
ground
potassium
2-8-7-2 excited
exited
The configuration listed on the periodic table is the
ground state electron configuration. In the chart below,
draw the ground state and excited state electron
configurations
Element
He
O
Na
F
Al
Mg
Br
Ground State
Excited State
Element
Ground State
Electron
Configuration
Ion
Ion’s Electron
Configuration
Na
Na
+
Mg
Mg
+2
Fe
Fe
+3
Al
Al
+3
Li
Li
+1
Quantum
• Electrons can only absorb or release energy in discrete, specific amounts.
• The amounts, or bundles of energy are called __________ (or _________)
corresponding to differences in energy levels of the orbitals/shells.
Electrons and Light
• An atom emits energy when the electron falls from high energy levels to
lower energy levels. This energy is in the form of ____________________.
• If the wavelength is in the ___________________________, the energy
can be seen as color.
Light Emission
• Each move from a particular energy level to a lower energy level will release
light of a specific wavelength.
• When certain elements are excited, they give off energy of a distinctive
color as the electron fall back down to lower energy levels. These colors are
specific and can be used to __________________________ (Flame Test).
Spectral lines
• If high voltage is applied to hydrogen gas confined in a gas tube, called a gas
discharge tube, light is emitted. If this light is passed through a prism, a
series of bright lines of distinct colors is produced. Bohr reasoned that
these different colored bands of
light were actually quanta of
corresponding energy. These quanta
were emitted as electrons of
hydrogen atoms returned from
their higher levels in the excited
state to their lower levels in the
ground state.
Bright Line Spectra
• Bright line spectrum = the series of
bright __________ produced when
excited electrons _____________
to their original energy levels
• Each element has its own unique set
of spectral lines which can
therefore be used to identify the
elements presence.
Valence Electrons
• Electrons that occupy the valence energy level
• Valence Electrons= found in ______________________ energy level
Na 2-8-1
Cl 2-8-7
• Atoms can have a maximum of 8 valence electrons
Lewis Dot Diagrams (Electron Dot Diagrams)
• Represent the arrangement of electrons around the nucleus.
• ____________ are the DOTS.
• _____________ is the symbol.
• ONLY REPRESENT _______________ ELECTRONS!!
•
Fill one side first, then one on each side before you pair electrons.
Na
B
O
Mg
Cl
Ne
Si
H
N