Question

Which of the following statements is(are) true regarding the atom? a. Negatively charged particles are embedded in a positively charged cloud throughout the atom. b. As verified by Rutherford, only positively charged particles called protons are found inside the nucleus. c. Electrons located further from the nucleus have more predictable behavior because they contain less energy. d. Electrons display both particle-like behavior (they have mass) and wave- like behavior (they are associated with probability). e. Niels Bohr showed that quantized energy is a continuous spectrum, like a ramp or the slope of a hill.

Short answer

Only statement d is true, as it states that electrons display both particle-like behavior (having mass) and wave-like behavior (associated with probability).

Step-by-step solution

Statement a

Negatively charged particles are embedded in a positively charged cloud throughout the atom. This statement refers to JJ Thomson's Plum Pudding model, which proposed that the negatively charged electrons were surrounded by a uniform positively charged cloud. However, this model was later disproved by Rutherford's Gold Foil Experiment, so statement a is not true.

Statement b

As verified by Rutherford, only positively charged particles called protons are found inside the nucleus. Rutherford's Gold Foil Experiment showed that almost all of an atom's mass is concentrated in the nucleus, where positively charged protons and neutral neutrons reside. Statement b incorrectly implies that there are only protons in the nucleus, so it is not true.

Statement c

Electrons located further from the nucleus have more predictable behavior because they contain less energy. This statement is not true. Electrons further from the nucleus actually have more energy, not less. Also, their behavior becomes less predictable because they interact with other electrons, and their probability distribution becomes more complex. So, statement c is not true.

Statement d

Electrons display both particle-like behavior (they have mass) and wave-like behavior (they are associated with probability). This statement is true. Electrons have been found to exhibit both particle-like properties, such as having mass and charge, as well as wave-like properties, such as interference and diffraction patterns. The dual nature of electrons is an essential concept in quantum mechanics. Therefore, statement d is true.

Statement e

Niels Bohr showed that quantized energy is a continuous spectrum, like a ramp or the slope of a hill. This statement is not true. Niels Bohr's model of the hydrogen atom showed that the energy levels of electrons in an atom have specific, discrete values, called quantized energy levels. The energy spectrum is not continuous; rather, it is comprised of distinct energy levels. So, statement e is not true. To summarize, among the given statements, only statement d is true regarding the atom.

Key concepts

Rutherford Model

The Rutherford Model revolutionized our understanding of atomic structure. Before this model, the widely accepted theory was J.J. Thomson's Plum Pudding Model. This older model suggested that negatively charged electrons floated within a "soup" of positive charge, much like raisins in pudding. Rutherford, however, proposed a different scenario through his famous Gold Foil Experiment.

The key findings of this experiment led Rutherford to describe the atom as having a small, dense, positively charged nucleus. Surrounding this nucleus, negatively charged electrons moved, like planets circling the sun. This was a groundbreaking shift away from the idea of uniform positive charge, showcasing a concentrated center of mass and positive charge inside the nucleus. Additionally, while Rutherford identified the presence of protons in the nucleus, he later clarified that neutral particles, called neutrons, also resided there along with protons.

Key features of the Rutherford Model include:

• A nucleus containing protons and neutrons.
• The electrons orbiting around the nucleus in various paths.
• The majority of an atom's volume being empty space, wherein the electrons orbit.

However, despite its success, the Rutherford Model couldn't explain certain observations, such as why electrons did not spiral into the nucleus due to attraction forces.

Bohr Model

The Bohr Model was a pivotal advancement in atomic theory, building on the limitations of the Rutherford Model. Proposed by Niels Bohr in 1913, this model was able to explain the stability of the hydrogen atom and its emission spectrum.

Bohr introduced the concept of quantized energy levels, a critical idea departed from the continuous energy spectrum notion. According to Bohr's propositions, electrons orbit the nucleus in fixed paths, or shells, without radiating energy. These orbits correspond to specific energy levels, which are quantized; meaning they are at set distances from the nucleus. When an electron moves between these levels, it absorbs or emits a quantum of energy.

Significant ideas of the Bohr Model include:

• Electrons orbit the nucleus at fixed distances, creating stable energy levels.
• Energy is absorbed or emitted in discrete values (quanta) when electrons jump between levels.
• The model specifically worked well for explaining the hydrogen atom's spectral lines.

Thus, the Bohr Model provided the first successful explanation for the observed hydrogen emission spectrum, although it did not efficiently explain more complex atoms or account for electron-electron interactions.

Quantum Mechanics

Quantum Mechanics is a fundamental theory in physics that succeeded these classical models of the atom, leading to a more complete understanding of electron behavior. Unlike previous models which used fixed paths for electron movement, Quantum Mechanics introduces the concept of orbitals, probability distributions where electrons might be found. This theory posits that electrons exhibit both particle and wave-like behaviors, a duality that is essential to understanding the nature of particles at atomic and subatomic levels.

The development of Quantum Mechanics addressed several issues that the Bohr Model could not resolve. It provides a more precise description of electron behavior and interactions within an atom by using mathematical functions known as wave functions. These complex equations yield probabilities of finding an electron in a given location around the nucleus, without precise paths for electrons.

Key concepts in Quantum Mechanics include:

• Wave-particle duality, where particles such as electrons display both characteristics.
• Heisenberg's Uncertainty Principle, stating the impossibility of simultaneously knowing an electron's exact position and momentum.
• The probabilistic nature of electron locations as determined by orbitals.

This framework allows scientists to make predictions and better understand phenomena at the quantum level, enabling advancements in various technological fields.

Electron Behavior

Electron behavior is a complex topic that underscores many elements of modern chemistry and physics. Understanding this behavior has been integral to advancements in atomic theory, particularly with the incorporation of Quantum Mechanics.

Electrons, while having mass and charge like particles, also exhibit wave-like properties. This dual nature is central to understanding interactions at a subatomic level. As electrons do not travel in fixed orbits, their positions are expressed as probability distributions or clouds around the nucleus. These regions, called orbitals, describe where an electron is likely to be found.

Important aspects of electron behavior include:

• The dual nature of electrons, having both particle and wave properties.
• The variation in energy levels, with those far from the nucleus possessing higher energy and less predictability in behavior due to increased interaction and complex distribution.
• Quantum superposition, allowing electrons to exist in multiple states until observed.

The inherently unpredictable and probabilistic nature of electron behavior does not detract from its significance in determining chemical properties and reactions. This behavior influences everything from the color of compounds to the way materials conduct electricity, illustrating its fundamental role in science.