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Questions and Answers
Which scientist is credited with the discovery of the electron?
Which scientist is credited with the discovery of the electron?
Which principle states that no two electrons in an atom can have the same set of quantum numbers?
Which principle states that no two electrons in an atom can have the same set of quantum numbers?
What does the atomic number (Z) represent in isotope notation?
What does the atomic number (Z) represent in isotope notation?
In the wave mechanical model, what term describes the regions where electrons are likely to be found?
In the wave mechanical model, what term describes the regions where electrons are likely to be found?
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What is a common limitation of the Bohr model?
What is a common limitation of the Bohr model?
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What particle was discovered by James Chadwick?
What particle was discovered by James Chadwick?
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According to the Aufbau Principle, how do electrons fill atomic sublevels?
According to the Aufbau Principle, how do electrons fill atomic sublevels?
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What is the mass number of an isotope if it has 6 protons and 8 neutrons?
What is the mass number of an isotope if it has 6 protons and 8 neutrons?
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Study Notes
Atomic History
- Democritus (400 BCE): Proposed the concept of indivisible particles called atoms.
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John Dalton (1803): Developed the atomic theory.
- Atoms are indivisible (later disproven).
- Atoms of the same element are identical.
- Atoms combine in fixed ratios to form compounds.
- J.J. Thomson (1897): Discovered the electron using the cathode ray tube, proposing the plum pudding model (electrons embedded in a positive matrix).
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Ernest Rutherford (1911): Performed the gold foil experiment, discovering the nucleus.
- Atoms are mostly empty space with a dense, positively charged nucleus.
- Niels Bohr (1913): Proposed electrons travel in specific energy levels around the nucleus.
- Erwin Schrödinger (1926): Developed the wave mechanical model, describing electrons in probabilistic regions called orbitals.
- James Chadwick (1932): Discovered the neutron, completing the atomic model.
Subatomic Particles
- Proton (p+): Charge +1, mass ≈ 1 amu, located in the nucleus.
- Neutron (n0): Charge 0, mass ≈ 1 amu, located in the nucleus.
- Electron (e−): Charge -1, mass ≈ 0.0005 amu, located in the electron cloud.
Isotopes
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Atoms of the same element with different numbers of neutrons.
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Isotope Notation: AZX (e.g., 146C)
- A: Mass number (protons + neutrons)
- Z: Atomic number (protons)
- X: Element symbol
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Calculating Neutrons: Mass Number - Atomic Number
Electron ConfigurationAtomic History
- Democritus (400 BCE): Proposed the concept of indivisible particles called atoms.
-
John Dalton (1803): Developed the atomic theory.
- Atoms are indivisible (later disproven).
- Atoms of the same element are identical.
- Atoms combine in fixed ratios to form compounds.
- J.J. Thomson (1897): Discovered the electron using the cathode ray tube, proposing the plum pudding model (electrons embedded in a positive matrix).
-
Ernest Rutherford (1911): Performed the gold foil experiment, discovering the nucleus.
- Atoms are mostly empty space with a dense, positively charged nucleus.
- Niels Bohr (1913): Proposed electrons travel in specific energy levels around the nucleus.
- Erwin Schrödinger (1926): Developed the wave mechanical model, describing electrons in probabilistic regions called orbitals.
- James Chadwick (1932): Discovered the neutron, completing the atomic model.
Subatomic Particles
- Proton (p+): Charge +1, mass ≈ 1 amu, located in the nucleus.
- Neutron (n0): Charge 0, mass ≈ 1 amu, located in the nucleus.
- Electron (e−): Charge -1, mass ≈ 0.0005 amu, located in the electron cloud.
Isotopes
-
Atoms of the same element with different numbers of neutrons.
-
Isotope Notation: AZX (e.g., 146C)
- A: Mass number (protons + neutrons)
- Z: Atomic number (protons)
- X: Element symbol
-
Calculating Neutrons: Mass Number - Atomic Number
Electron Configuration
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Describes the arrangement of electrons in an atom's energy levels.
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Sublevel Filling Order:1s, 2s, 2p, 3s, 3p , 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s...
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Pauli Exclusion Principle: No two electrons can have the same set of quantum numbers.
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Aufbau Principle: Electrons fill lower energy sublevels first.
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Hund's Rule: Electrons occupy orbitals of the same sublevel singly before pairing.
Examples: Carbon (6)
- Electron Configuration: 1s22s22p2
Atomic Models
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Bohr Model: Electrons orbit the nucleus in specific energy levels. Energy is absorbed/emitted when electrons change levels. Limitations exist when dealing with multi-electron systems.
-
Wave Mechanical Model: (Schrödinger Model): Electrons exist in orbitals (probabilistic regions), making it more accurate for multi-electron systems.
-
Describes the arrangement of electrons in an atom's energy levels.
-
Sublevel Filling Order:1s, 2s, 2p, 3s, 3p , 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s...
-
Pauli Exclusion Principle: No two electrons can have the same set of quantum numbers.
-
Aufbau Principle: Electrons fill lower energy sublevels first.
-
Hund's Rule: Electrons occupy orbitals of the same sublevel singly before pairing.
Examples: Carbon (6)
- Electron Configuration: 1s22s22p2
Atomic Models
- Bohr Model: Electrons orbit the nucleus in specific energy levels. Energy is absorbed/emitted when electrons change levels. Limitations exist when dealing with multi-electron systems.
- Wave Mechanical Model: (Schrödinger Model): Electrons exist in orbitals (probabilistic regions), making it more accurate for multi-electron systems.
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Description
Explore the fascinating evolution of atomic theory from Democritus to Chadwick in this quiz. Learn about key contributions and discoveries that shaped our understanding of the atom and its subatomic components. Test your knowledge on the scientists and their groundbreaking experiments.
