exit ticket summary - history of the atomic model (b) fill in the blanks in the table below to create summary notes on the different atomic models that have been developed. the first section has been done for you. | model | scientist | date | contribution to the atomic model | |-------|-----------|------|----------------------------------| | image of solid sphere | democritus | 5th century bce | - greek philosopher who created the first idea of atoms
- stated that matter is made of tiny uncuttable spheres called \atomos\ which is greek for indivisible.
- atoms of different materials differed, atoms were in constant motion, and atoms could combine with each other. | | image of two spheres | john dalton | 1808 | - english teacher who created the first true ____ ____.
- performed experiments that found that substances always combined in strict ____ ____.
- stated that atoms are ____ spheres, atoms of one element are ____, atoms of different elements are ____, and ____ are combinations of atoms. | | image of sphere with dots | j.j. thomson | 1897 | - english physicist who created the ____ ____ model.
- performed experiments that found cathode rays were made of negatively-charged particles called ____ that were smaller than the atom; the first subatomic particle discovered.
- stated that atoms were composed of negatively-charged electrons scattered through a ball made of ____ charge. | | image of planetary model | ernest rutherford | 1911 | - english physicist who created the ____ model.
- performed experiments that shot positively-charged alpha particles at ____ foil; most went through but some scattered.
- stated that atoms were mostly ____ with a dense, positively-charged ____ with negatively-charged electrons surrounding it. discovered ____ in 1919. | | image of bohr model | neils bohr | 1913 | - danish physicist who created the ____ model.
- used rutherford’s data to show that electrons are arranged in circular ____, similar to planets in a solar system.
- stated that electrons move around the nucleus in orbits based on their ____. electrons closer to the nucleus have ____ energy, electrons further away have ____. | | image of electron cloud | erwin schrodinger | 1926 | - austrian physicist who created the ____ model.
- used complex math to show that electrons don’t move in set orbits, but move as ____.
- stated that atoms had a nucleus surrounded by an ____ ____. the probability of finding an electron is ____ where the cloud is densest and ____ where it is less dense. | | image of nucleus with neutron | james chadwick | 1932 | - english physicist who discovered the ____.
- performed experiments that shot positively-charged alpha particles at ____ and found a new kind of radiation.
- proposed that the radiation was made of subatomic particles called neutrons equal in mass to ____ that had a ____ charge. neutrons are found in the ____. |

Question

Accepted Answer

### John Dalton (1808)
- **Contribution blanks**:
    - First true **atomic theory**
    - Substances combined in strict **numerical ratios** (or "fixed proportions")
    - Atoms are **solid** spheres, atoms of one element are **identical**, atoms of different elements are **different**, and **compounds** are combinations of atoms.

### J.J. Thomson (1897)
- **Contribution blanks**:
    - Created the **plum pudding** model
    - Cathode rays made of negatively - charged particles called **electrons**
    - Atoms composed of electrons scattered through a ball made of **positive** charge.

### Ernest Rutherford (1911)
- **Contribution blanks**:
    - Created the **nuclear** model
    - Shot alpha particles at **gold** foil
    - Atoms mostly **empty space** with a dense, positively - charged **nucleus**; discovered **protons** in 1919.

### Niels Bohr (1913)
- **Contribution blanks**:
    - Created the **planetary** (or "Bohr") model
    - Electrons arranged in circular **orbits**
    - Electrons move based on their **energy**; electrons closer to nucleus have **less** energy, further away have **more** energy.

### Erwin Schrödinger (1926)
- **Contribution blanks**:
    - Created the **quantum mechanical** (or "electron cloud") model
    - Electrons move as **waves**
    - Atoms have a nucleus surrounded by an **electron cloud**; probability of finding electron is **high** where cloud is densest, **low** where less dense.

### James Chadwick (1932)
- **Contribution blanks**:
    - Discovered the **neutron**
    - Shot alpha particles at **beryllium**
    - Neutrons equal in mass to **protons** with a **neutral** charge; found in the **nucleus**.

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QUESTION IMAGE

Question

Explanation:

John Dalton (1808)

J.J. Thomson (1897)

Ernest Rutherford (1911)

Niels Bohr (1913)

Erwin Schrödinger (1926)

James Chadwick (1932)

Answer: