4.3 Modern Atomic Theory What can happen when an atom absorbs energy? - an increase in kinetic energy or a phase change energy may be absorbed by an atom,
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4.3 Modern Atomic Theory
What can happen when an atom absorbs energy?
- an increase in kinetic energy or a phase change
energy may be absorbed by an atom, then emitted as light
4.3 Modern Atomic Theory
Niels Bohr (1885-1962)
agreed with Rutherford’s model but added something to it
energy levels – the possible energies that electrons in an atom can have
4.3 Modern Atomic Theory
when an atom gains energy an electron may move to a higher energy level
when it loses the energy it emits it as light
no two elements have the same set of energy levels, so the emit different colors of light
4.3 Modern Atomic Theory
Electron Cloud Model
electron cloud model – model of the most likely locations for electrons in an atom (deals with probability)
4.3 Modern Atomic Theory
Electron Cloud Model of a Hydrogen Atom
4.3 Modern Atomic Theory
4.3 Modern Atomic Theory
orbital – region of space where an electron is likely to be found
4.3 Modern Atomic Theory
electron cloud – a good approximation of how electrons behave in their orbitals
Energy Level, Orbitals, and ElectronsEnergy Level, Orbitals, and Electrons
Energy LevelEnergy Level Number of Number of OrbitalsOrbitals
Maximum # of Maximum # of ElectronsElectrons
11 11 22
22 44 88
33 99 1818
44 1616 3232
4.3 Modern Atomic Theory
electron configuration – arrangement of electrons in the orbital of an atom
ground state – electrons are all in their lowest possible energy levels (most stable)
excited state – one or more electrons are in a higher energy level than usual (least stable)
atoms emit light when their electrons return to ground state
Chapter 4 Vocabulary
nucleus
electron cloud
neutron
proton
electron
atomic number
energy levels
ground state
mass number
isotopes
orbital
electron configuration
excited state
Chapter 4 Vocabulary
nucleus
electron cloud
neutron
proton
electron
atomic number
energy levels
ground state
mass number
isotopes
orbital
excited state
Chapter 4 Vocabulary
electron cloud
neutron
proton
electron
atomic number
energy levels
ground state
mass number
isotopes
orbital
excited state
Chapter 4 Vocabulary
electron cloud
proton
electron
atomic number
energy levels
ground state
mass number
isotopes
orbital
excited state
Chapter 4 Vocabulary
electron cloud
proton
electron
atomic number
energy levels
ground state
mass number
isotopes
excited state
Chapter 4 Vocabulary
electron cloud
proton
electron
atomic number
energy levels
ground state
mass number
isotopes
Chapter 4 Vocabulary
electron cloud
proton
electron
energy levels
ground state
mass number
isotopes
Chapter 4 Vocabulary
electron cloud
proton
electron
energy levels
ground state
mass number
Chapter 4 Vocabulary
electron cloud
proton
electron
ground state
mass number
Chapter 4 Vocabulary
electron cloud
proton
electron
ground state
Chapter 4 Vocabulary
proton
electron
ground state
Chapter 4 Vocabulary
proton
electron
Chapter 4 Vocabulary
proton
Chapter 4 Vocabulary
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