1.3.1 Historical models: Dalton, Thomson, Rutherford, Bohr

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Cards (53)

Who proposed the atomic model that describes matter as indivisible spheres?
Dalton
What is the relationship between electrons and positively charged matter in the image?
Electrons are negatively charged particles
Positively charged matter is attracted to the electrons
This attraction holds the atom together
What is the name of the device shown in the image?
Detector
What principle did Dalton's work confirm regarding atoms?
The principle of conservation of mass
How did Rutherford's experiment impact our understanding of atomic structure?
It revolutionized our understanding of atomic structure
How does the water molecule form according to Dalton's Atomic Theory?
1 oxygen atom (16 mass units)
2 hydrogen atoms (2 mass units each)
Total mass of water molecule = 18 mass units
How many mass units do 2 hydrogen atoms have?
2 mass units
What did the results of Rutherford's experiment indicate about the atom's structure?
Atoms are mostly empty space
What are the key components of the Bohr atomic model?
Nucleus with protons and neutrons
Electrons orbiting the nucleus in discrete energy levels
Electrons can only occupy certain allowed energy levels
Electrons can jump between energy levels by absorbing or emitting photons
What did Rutherford discover in his model?
The nucleus, a dense center of the atom
What does it mean when particles deflect slightly in Rutherford's experiment?
They are bouncing off positive charges
What does Dalton's atomic model suggest about matter?
It is made of tiny indivisible spheres
What were the key findings from Rutherford's gold foil experiment?
Most particles passed through - atom mostly empty space
Some particles deflected slightly - indicating positive charges
Very few particles bounced back - suggesting a dense core
What type of particle is represented by the gray spheres in the image?
Neutron
What is the name given to the positively charged matter in the image?
Positively charged matter
What are the key features of Dalton's Atomic Model?
Matter is made of tiny indivisible spheres
Matter is discrete, not continuous
Confirms conservation of mass
Atoms join but do not disappear
What are the negatively charged particles in an atom called?
Electrons
What type of particle is represented by the green and orange spheres in the image?
Proton
What was a significant limitation of Thomson's Plum Pudding Model?
It did not account for the nucleus
What type of particle is represented by the blue spheres in the image?
Electron
How does the image illustrate the concept of atomic structure?
The positively charged matter represents the nucleus
The electrons are arranged around the nucleus
This arrangement demonstrates the basic structure of an atom
The attraction between the electrons and nucleus contributes to atomic stability
How can the Bohr model be used to calculate the energy levels of an electron in a hydrogen atom?
The energy of an electron in the nth energy level is given by:
$E_n =$ $-\frac{13.6\text{ eV}}{n^2}$
Where n is the principal quantum number (1, 2, 3, ...)
This equation can be used to determine the allowed energy levels of an electron in a hydrogen atom
What is the name of the theory shown in the image?
Dalton's Atomic Theory
What is the name of the particle shown flowing through the device?
α-particle
What is the name of the radioactive material shown in the image?
Radium
What led to the rejection of Thomson's Plum Pudding Model?
The discovery of the nucleus showed it was incorrect
What are the key features of the Bohr model of the atom?
Electrons orbit the nucleus
Fixed energy levels or electron shells
Shells are like staircase steps
Each shell holds a specific number of electrons
What are the key features of Thomson's Plum Pudding Model?
Atom is a positive sphere
Negative electrons are evenly distributed
Improvement over Dalton's model
What analogy is used to describe electron shells in the Bohr model?
Like staircase steps
What are the key components of Dalton's Atomic Theory?
All matter is made up of tiny indivisible particles called atoms
Atoms of the same element are identical, while atoms of different elements have different properties
Atoms cannot be created, divided, or destroyed
Atoms combine in simple whole-number ratios to form compounds
What did Rutherford use in his experiment?
Alpha particles and thin gold foil
How does the lead block in the device function?
The lead block shields the detector from external radiation
This allows the detector to focus on measuring the α-particles from the radium source
What does the image suggest about the stability of an atom?
The attraction between the electrons and positively charged matter holds the atom together
This arrangement suggests the atom is stable
Any disruption to this balance could make the atom unstable
What does Thomson's Plum Pudding Model describe the atom as?
A positive sphere with negative electrons
What is the purpose of the thin gold foil in the device?
The thin gold foil is used to detect the flow of α-particles
It allows the α-particles to pass through and be detected
How does the Bohr model differ from the modern quantum mechanical model of the atom?
Bohr model depicts electrons in circular orbits, while quantum model describes electrons in probabilistic wave functions
Bohr model has discrete energy levels, while quantum model has a continuous range of energy levels
Bohr model is a simplified classical model, while quantum model is based on quantum mechanics
How does the detector in the device work to detect the α-particles?
The detector measures the deflection or scattering of the α-particles as they pass through the thin gold foil
This allows the properties of the α-particles to be studied
What does the Bohr model show about electrons?
Electrons orbit the nucleus at fixed energy levels
What is the name of the atomic model shown in the image?
Bohr atomic model
How do atoms behave according to Dalton's atomic model?
Atoms join but never disappear