Electronic Structure of Matter worksheet covering Bohr's model and quantum mechanical concepts.

Let's solve the worksheet step by step and provide explanations for each answer.

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I. Complete the sentence

1. An instrument that is used to analyze the colors given off by the vapors of elements is called
→ Spectroscope
*Explanation:* A spectroscope is an instrument that separates light into its component wavelengths (colors), allowing scientists to analyze the emission spectra of elements.

2. Bohr considered the electrons as particles moving around the ________ in fixed ________ orbits.
→ nucleus, circular
*Explanation:* In Bohr’s model, electrons orbit the nucleus in specific circular paths or orbits.

3. These orbits, called ________, are found at ________ distances from the nucleus.
→ energy levels, fixed
*Explanation:* The orbits are also known as energy levels, and each level is at a fixed distance from the nucleus.

4. Electrons in each orbit have ________ energy.
→ definite
*Explanation:* According to Bohr, electrons in a particular orbit have a definite amount of energy.

5. A state in which an electron moves to a higher energy level as it absorbs an extra energy is called ________.
→ excited state
*Explanation:* When an electron absorbs energy and jumps to a higher energy level, it is said to be in an excited state.

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II. Matching Column

Match the scientist (Column A) with their contribution (Column B).

| Column A | Column B |
|---------|---------|
| 1. Rutherford | d. Atom is mostly empty space. |
| 2. Bohr | a. Electrons have definite energy. |
| 3. De Broglie | e. Electron is both a wave and a particle. |
| 4. Schrödinger | c. Developed a mathematical equation to find probable location of an electron. |
| 5. Heisenberg | b. Electron cannot be located exactly. |

#### Explanation:

- Rutherford: His gold foil experiment led to the conclusion that the atom is mostly empty space with a dense nucleus.
- Bohr: Proposed that electrons occupy fixed energy levels and can jump between them by absorbing or emitting energy.
- De Broglie: Proposed the wave-particle duality of electrons — electrons behave like both waves and particles.
- Schrödinger: Developed the Schrödinger equation, which describes how the quantum state of a physical system changes over time and helps determine the probability of finding an electron in a certain region.
- Heisenberg: Formulated the uncertainty principle, stating that we cannot simultaneously know the exact position and momentum of an electron.

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✔ Final Answers:

#### I. Complete the sentence
1. Spectroscope
2. nucleus, circular
3. energy levels, fixed
4. definite
5. excited state

#### II. Matching Column
1. Rutherford → d
2. Bohr → a
3. De Broglie → e
4. Schrödinger → c
5. Heisenberg → b

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This worksheet covers key concepts in atomic structure, especially focusing on Bohr’s model and the evolution of atomic theory through contributions from major scientists.