Based on the alpha-particle scattering experiment, Rutherford concluded that: 1. Most of the space inside the atom is empty. 2. The positive charge of the atom occupies a very large volume. 3. The mass of the atom is distributed evenly throughout its volume. Which of the statements given above is/are correct?

The correct option is (a). Explanation Ernest Rutherford’s alpha-particle scattering experiment (1911) was pivotal in determining the internal structure of the atom. By bombarding a thin gold foil with high-energy alpha particles, Rutherford challenged the existing "plum pudding" model proposed by J.J. Thomson and established the nuclear model of the atom. Statement-wise Analysis: - Statement 1 is Correct: In the experiment, it was observed that the vast majority of alpha particles passed through the gold foil without any deflection. This observation led to the conclusion that most of the space inside an atom is empty, allowing particles to pass through unhindered. - Statement 2 is Incorrect: Only a small fraction of alpha particles were deflected by small angles. This indicated that the positive charge is not distributed over the entire volume of the atom (as suggested by Thomson). Instead, the positive charge is concentrated in a very small volume relative to the total size of the atom. - Statement 3 is Incorrect: A very tiny fraction of alpha particles (approximately 1 in 20,000) rebounded back by 180 degrees. This observation suggested that nearly all the mass of the atom is concentrated in a dense central core (the nucleus), rather than being distributed evenly throughout the atomic volume. Key Takeaway: Rutherford's model characterizes the atom as mostly empty space with a tiny, dense, positively charged nucleus at the center, which contains nearly all of the atom's mass.

NCERT Class 9 Science — Chapter 4: Structure of the atom

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Based on the alpha-particle scattering experiment, Rutherford concluded that:

Most of the space inside the atom is empty.
The positive charge of the atom occupies a very large volume.
The mass of the atom is distributed evenly throughout its volume.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (a).

Explanation

Ernest Rutherford’s alpha-particle scattering experiment (1911) was pivotal in determining the internal structure of the atom. By bombarding a thin gold foil with high-energy alpha particles, Rutherford challenged the existing "plum pudding" model proposed by J.J. Thomson and established the nuclear model of the atom.

Statement-wise Analysis:

Statement 1 is Correct: In the experiment, it was observed that the vast majority of alpha particles passed through the gold foil without any deflection. This observation led to the conclusion that most of the space inside an atom is empty, allowing particles to pass through unhindered.
Statement 2 is Incorrect: Only a small fraction of alpha particles were deflected by small angles. This indicated that the positive charge is not distributed over the entire volume of the atom (as suggested by Thomson). Instead, the positive charge is concentrated in a very small volume relative to the total size of the atom.
Statement 3 is Incorrect: A very tiny fraction of alpha particles (approximately 1 in 20,000) rebounded back by 180 degrees. This observation suggested that nearly all the mass of the atom is concentrated in a dense central core (the nucleus), rather than being distributed evenly throughout the atomic volume.

Key Takeaway:

Rutherford's model characterizes the atom as mostly empty space with a tiny, dense, positively charged nucleus at the center, which contains nearly all of the atom's mass.

Your note

More from Chapter 4: Structure of the atom

Which sub-atomic particle was identified by J. Chadwick in 1932?

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With reference to Neils Bohr’s model of the atom, consider the following statements: 1. Only certain special orbits known as discrete orbits of electrons are allowed inside the atom. 2. Electrons radiate energy continuously while revolving in discrete orbits. 3. These discrete orbits are called energy levels. Which of the statements given above is/are correct?

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Consider the following statements regarding the discovery and properties of neutrons: 1. They were discovered by J.J. Thomson in 1897. 2. They are present in the nucleus of all atoms including hydrogen. 3. A neutron has no charge and a mass nearly equal to that of a proton. Which of the statements given above is/are correct?

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With reference to 'Valency', consider the following statements: 1. It is the combining capacity of the atoms of elements. 2. Atoms react to achieve a duplet in the outermost shell in all cases. 3. If the outermost shell has 8 electrons, the valency is 8. Which of the statements given above is/are correct?

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With reference to the definition of an element, consider the following statements: 1. Elements are defined by the number of protons they possess. 2. Atoms of a given element can have different numbers of protons. 3. The atomic number is characteristic of a particular element.

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The correct option is (a).

Explanation

Statement-wise Analysis:

Statement 1 is Correct: In the experiment, it was observed that the vast majority of alpha particles passed through the gold foil without any deflection. This observation led to the conclusion that most of the space inside an atom is empty, allowing particles to pass through unhindered.
Statement 2 is Incorrect: Only a small fraction of alpha particles were deflected by small angles. This indicated that the positive charge is not distributed over the entire volume of the atom (as suggested by Thomson). Instead, the positive charge is concentrated in a very small volume relative to the total size of the atom.
Statement 3 is Incorrect: A very tiny fraction of alpha particles (approximately 1 in 20,000) rebounded back by 180 degrees. This observation suggested that nearly all the mass of the atom is concentrated in a dense central core (the nucleus), rather than being distributed evenly throughout the atomic volume.

Key Takeaway:

Rutherford's model characterizes the atom as mostly empty space with a tiny, dense, positively charged nucleus at the center, which contains nearly all of the atom's mass.