3.4 energy levels in atoms electrons in atoms electrons are attracted to a positive nucleus by...
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3.4 Energy levels in atoms
Electrons in atoms
Electrons are attracted to a positive nucleus by electrostatic force
Electrons move about in allowed orbits or shells with different energy levels
The lowest energy state of an atom is called its ground state
When an atom in its ‘ground’ stateabsorbs energy, one of its electrons moves to a shell at higher energy. The atom is now in an ‘excited’ stateleaving a vacancy in the shell.
3.4 Energy levels in atoms
Electrons in atoms
Electrons are attracted to a positive nucleus by electrostatic force
Electrons move about in allowed orbits or shells with different energy levels
The lowest energy state of an atom is called its ground state
When an atom in its ‘ground’ stateabsorbs energy, one of its electrons moves to a shell at higher energy. The atom is now in an ‘excited’ stateleaving a vacancy in the shell.
3.4 Energy levels in atoms
Electrons in atoms
Electrons are attracted to a positive nucleus by electrostatic force
Electrons move about in allowed orbits or shells with different energy levels
The lowest energy state of an atom is called its ground state
When an atom in its ‘ground’ stateabsorbs energy, one of its electrons moves to a shell at higher energy. The atom is now in an ‘excited’ stateleaving a vacancy in the shell.
3.4 Energy levels in atoms
Electrons in atoms
Electrons are attracted to a positive nucleus by electrostatic force
Electrons move about in allowed orbits or shells with different energy levels
The lowest energy state of an atom is called its ground state
When an atom in its ‘ground’ stateabsorbs energy, one of its electrons moves to a shell at higher energy. The atom is now in an ‘excited’ stateleaving a vacancy in the shell.
3.4 Energy levels in atoms
Electrons in atoms
Electrons are attracted to a positive nucleus by electrostatic force
Electrons move about in allowed orbits or shells with different energy levels
The lowest energy state of an atom is called its ground state
When an atom in its ‘ground’ stateabsorbs energy, one of its electrons moves to a shell at higher energy. The atom is now in an ‘excited’ stateleaving a vacancy in the shell.
De-excitation
An excited atom is unstable and the vacancy in the shell is soon filled by an electron from an outer shell dropping to a lower energy level emitting a photon.
De excitation of a mercury atommay proceed indirectly to the ground state via an intermediate state.
5.7 eV
4.9 eV
O eV
0.8 eV photon
4.9 eV photon
De-excitation
An excited atom is unstable and the vacancy in the shell is soon filled by an electron from an outer shell dropping to a lower energy level emitting a photon.
De excitation of a mercury atommay proceed indirectly to the ground state via an intermediate state.
5.7 eV
4.9 eV
O eV
0.8 eV photon
4.9 eV photon
De-excitation
An excited atom is unstable and the vacancy in the shell is soon filled by an electron from an outer shell dropping to a lower energy level emitting a photon.
De excitation of a mercury atommay proceed indirectly to the ground state via an intermediate state.
5.7 eV
4.9 eV
O eV
0.8 eV photon
4.9 eV photon
De-excitation
An excited atom is unstable and the vacancy in the shell is soon filled by an electron from an outer shell dropping to a lower energy level emitting a photon.
De excitation of a mercury atommay proceed indirectly to the ground state via an intermediate state.
5.7 eV
4.9 eV
O eV
0.8 eV photon
4.9 eV photon
Excitation using photons
An electron in an atom can absorb an incident photon’s energy if the photons energy exactly matches the quantum of energy required for excitation.
Excitation using photons
An electron in an atom can absorb an incident photon’s energy if the photons energy exactly matches the quantum of energy required for excitation.
The atoms of a fluorescent substance may get excited by incident uv light.
These atoms then de-excite emitting visible light.
Fluorescence
In the Starter ( a time delay switch): an electric current warms the filament electrodes.During the first second argon vapor in the starter conducts and warms up a bimetallic strip which bends and switches off the current flowing through the filament electrodes.The mains voltage then acts across the filament electrodes causing the gas to glow. http://home.howstuffworks.com/question337.htm/printable
Uv 217 nm
IR 1546 nm
UV 252 nm
The atoms of a fluorescent substance may get excited by incident uv light.
These atoms then de-excite emitting visible light.
Fluorescence
In the Starter ( a time delay switch): an electric current warms the filament electrodes.During the first second argon vapor in the starter conducts and warms up a bimetallic strip which bends and switches off the current flowing through the filament electrodes.The mains voltage then acts across the filament electrodes causing the gas to glow. http://home.howstuffworks.com/question337.htm/printable
The atoms of a fluorescent substance may get excited by incident uv light.
These atoms then de-excite emitting visible light.
Fluorescence
In the Starter ( a time delay switch): an electric current warms the filament electrodes.During the first second argon vapor in the starter conducts and warms up a bimetallic strip which bends and switches off the current flowing through the filament electrodes.The mains voltage then acts across the filament electrodes causing the gas to glow. http://home.howstuffworks.com/question337.htm/printable
The atoms of a fluorescent substance may get excited by incident uv light.
These atoms then de-excite emitting visible light.
Fluorescence
In the Starter ( a time delay switch): an electric current warms the filament electrodes.During the first second argon vapor in the starter conducts and warms up a bimetallic strip which bends and switches off the current flowing through the filament electrodes.The mains voltage then acts across the filament electrodes causing the gas to glow. http://home.howstuffworks.com/question337.htm/printable
The atoms of a fluorescent substance may get excited by incident uv light.
These atoms then de-excite emitting visible light.
Fluorescence
In the Starter ( a time delay switch): an electric current warms the filament electrodes.During the first second argon vapor in the starter conducts and warms up a bimetallic strip which bends and switches off the current flowing through the filament electrodes.The mains voltage then acts across the filament electrodes causing the gas to glow. http://home.howstuffworks.com/question337.htm/printable
Uv 217 nm
IR 1546 nm
UV 252 nm
The atoms of a fluorescent substance may get excited by incident uv light.
These atoms then de-excite emitting visible light.
Fluorescence
In the Starter (a time delay switch): an electric current warms the filament electrodes.During the first second argon vapor in the starter conducts and warms up a bimetallic strip which bends and switches off the current flowing through the filament electrodes.The mains voltage then acts across the filament electrodes causing the gas to glow. http://home.howstuffworks.com/question337.htm/printable
Uv 217 nm
IR 1546 nm
UV 252 nm
The atoms of a fluorescent substance may get excited by incident uv light.
These atoms then de-excite emitting visible light.
Fluorescence
In the Starter (a time delay switch): an electric current warms the filament electrodes.During the first second argon vapor in the starter conducts and warms up a bimetallic strip which bends and switches off the current flowing through the filament electrodes.The mains voltage then acts across the filament electrodes causing the gas to glow. http://home.howstuffworks.com/question337.htm/printable
Uv 217 nm
IR 1546 nm
UV 252 nm
The atoms of a fluorescent substance may get excited by incident uv light.
These atoms then de-excite emitting visible light.
Fluorescence
In the Starter (a time delay switch): an electric current warms the filament electrodes.During the first second argon vapor in the starter conducts and warms up a bimetallic strip which bends and switches off the current flowing through the filament electrodes.The mains voltage then acts across the filament electrodes causing the gas to glow. http://home.howstuffworks.com/question337.htm/printable
Uv 217 nm
IR 1546 nm
UV 252 nm
Fluorescence
In the Starter ( a time delay switch): an electric current warms the filament electrodes.During the first second argon vapor in the starter conducts and warms up a bimetallic strip which bends and switches off the current flowing through the filament electrodes.The mains voltage then acts across the filament electrodes causing the gas to glow. http://home.howstuffworks.com/question337.htm/printable