Question

True or false? Rutherford's bombardment experiments with metal foil suggested that the \(\alpha\) particles were being deflected by coming near a large, positively charged atomic nucleus.

Short answer

True. Rutherford's bombardment experiments with metal foil suggested that the α particles were being deflected by coming near a large, positively charged atomic nucleus, providing evidence for the existence of a dense, positively charged nucleus at the center of the atom.

Step-by-step solution

Background of Rutherford's Experiment

In Rutherford's gold foil experiment, he fired α particles (positively charged helium nuclei) at a very thin gold foil. He then observed the scattering pattern of the α particles using a screen coated with zinc sulfide. Most of the α particles passed straight through the foil, but some were deflected, and a few even bounced back.

Interpretation of Experimental Findings

Rutherford concluded from his experiment that atoms must have a small, dense, positively charged core known as the nucleus. The majority of the α particles passed through the foil with no deflection because they did not come close to the small, dense nucleus, which occupies a tiny fraction of the total volume of the atom. However, when α particles came close to the nucleus, they experienced a strong repulsive force from the positively charged nucleus, causing them to be deflected.

Evaluate the Statement

Based on the interpretation of Rutherford's experimental findings in Step 2, we can see that the statement "Rutherford's bombardment experiments with metal foil suggested that the α particles were being deflected by coming near a large, positively charged atomic nucleus" is indeed true. Rutherford's experiment provided crucial evidence for the existence of a dense, positively charged nucleus at the center of the atom. Correct answer: True

Key concepts

Atomic Structure

The concept of atomic structure is fundamental in understanding the nature of matter. Matter is made up of atoms, which are extremely small particles. Atoms are composed of three primary subatomic particles:

• Protons, which carry a positive charge
• Neutrons, which are neutral
• Electrons, which carry a negative charge

The arrangement of these particles within an atom determines its characteristics and behavior.
Protons and neutrons are found in an atom's nucleus, which is at the center. This nucleus is usually dense and positively charged due to the presence of protons. Electrons orbit around the nucleus in energy levels or shells.
The structure of the atom is crucial for understanding chemical reactions and interactions. Rutherford's experiments contributed significantly to the current understanding of atomic structure, revealing the existence of a central nucleus.

Nuclear Model of the Atom

The nuclear model of the atom was a revolutionary concept that emerged from Rutherford's gold foil experiment. Prior to this, the "plum pudding model," suggested by J.J. Thomson, depicted atoms as a diffuse cloud of positive charge with electrons scattered within.
However, Rutherford proposed a new model where:

• The atom consists of a tiny, dense, positively charged nucleus at its center.
• Surrounding this nucleus is a cloud of negatively charged electrons.

This model explained the deflection of \( \alpha \) particles in his experiments since only a dense, positively charged core could cause such a strong repulsive force. The nuclear model laid the groundwork for further developments in atomic theory, including the discovery of neutrons and the development of quantum mechanics.
It demonstrated that most of an atom's mass is concentrated in its nucleus while the electrons occupy the majority of its volume.

α Particles Scattering

In the context of atomic physics, the scattering of \( \alpha \) particles is a pivotal concept, primarily illustrated by Rutherford's gold foil experiment.
Alpha particles, which are helium nuclei composed of two protons and two neutrons, are positively charged. When these particles were directed at a thin sheet of gold, several outcomes were observed:

• Most \( \alpha \) particles passed through without any deviation, indicating empty space within the atom.
• Some particles were slightly deflected, hinting at a concentrated charge somewhere within the atom.
• A few particles were deflected at large angles, with some bouncing straight back, which suggested the presence of a dense and positively charged nucleus.

These observations were crucial for concluding that a small nucleus exists within each atom.
Thus, \( \alpha \) particle scattering helped establish the nuclear model and challenged previous atomic models. It highlighted the effectiveness of experimental physics in advancing the understanding of atomic structure.