Which statement best describes an electron

An electron **has a smaller mass than a proton** and **a negative charge** ($ m_e \approx 9.109 \times 10^{-31} $ kg).

The electron is a subatomic particle with the following properties: - **Charge**: The electron carries a **negative charge**. - **Mass**: The mass of an electron is significantly smaller than that of a proton. The mass of an electron $ m_e $ is approximately $ 9.109 \times 10^{-31} $ kilograms, while the mass of a proton $ m_p $ is approximately $ 1.673 \times 10^{-27} $ kilograms. $$ m_e \approx 9.109 \times 10^{-31} \, \text{kg} $$ $$ m_p \approx 1.673 \times 10^{-27} \, \text{kg} $$ Given these properties, the statement that best describes an electron is: **"It has a smaller mass than a proton and a negative charge."**

15 Aug, 2024

· Physics

It has a smaller mass than a proton and a negative charge
It has a smaller mass than a proton and a positive charge
It has a greater mass than a proton and a negative charge
It has a greater mass than a proton and a positive charge

Short Answer

Some answer Some answer Some answer

Long Explanation

Explanation

The electron is a subatomic particle with the following properties:

Charge: The electron carries a negative charge.
Mass: The mass of an electron is significantly smaller than that of a proton. The mass of an electron $m_e$ is approximately $9.109 \times 10^{-31}$ kilograms, while the mass of a proton $m_p$ is approximately $1.673 \times 10^{-27}$ kilograms.

m_e \approx 9.109 \times 10^{-31} \, \text{kg}

m_p \approx 1.673 \times 10^{-27} \, \text{kg}

Given these properties, the statement that best describes an electron is:

"It has a smaller mass than a proton and a negative charge."

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Richard Hamilton

Physics Content Writer at Math AI

Richard Hamilton holds a Master’s in Physics from McGill University and works as a high school physics teacher and part-time contract writer. Using real-world examples and hands-on activities, he explains difficult concepts in physics effectively.

physics

Concept

Subatomic Particles

Role of Subatomic Particles in Atoms

Subatomic particles are the building blocks of atoms, consisting primarily of protons, neutrons, and electrons. Each of these particles has unique properties and plays a crucial role in the structure and behavior of atoms.

Protons

Protons are positively charged particles located in the nucleus of an atom. They determine the atomic number ( $Z$ ) of an element, which defines the element itself. For instance, a carbon atom always has 6 protons. The number of protons is given by:

Z = \text{number of protons}

Neutrons

Neutrons are neutral particles, meaning they have no charge. They also reside in the nucleus and contribute to the atom's mass. The number of neutrons can vary in atoms of the same element, resulting in different isotopes. The mass number ( $A$ ) of an atom is the sum of protons and neutrons:

A = Z + \text{number of neutrons}

Electrons

Electrons are negatively charged particles that orbit the nucleus in various energy levels or shells. The number of electrons in a neutral atom equals the number of protons. Electrons determine the chemical behavior of an atom, including how it bonds with other atoms.

\text{Number of electrons in a neutral atom} = Z

Interactions and Forces

The strong nuclear force binds protons and neutrons together in the nucleus, overcoming the repulsive electrostatic force between protons due to their positive charge. The electromagnetic force is responsible for the attraction between electrons and protons, keeping electrons in their orbits around the nucleus.

Quantum Mechanics

The behavior of subatomic particles is described by quantum mechanics, which provides a framework for understanding their wave-particle duality and the probabilistic nature of their positions and energies. The Schrödinger equation, for example, is used to describe how the quantum state of a physical system changes with time:

i\hbar\frac{\partial \psi}{\partial t} = \hat{H}\psi

Here, $\psi$ is the wave function, $\hbar$ is the reduced Planck constant, and $\hat{H}$ is the Hamiltonian operator corresponding to the total energy of the system.

Summary

Understanding subatomic particles is fundamental to comprehending atomic structure and the behavior of matter at a microscopic level. Their interactions and properties are essential for explaining a wide range of physical phenomena and underpin much of modern physics and chemistry.

Concept

Charge

Understanding Electric Charge

Electric charge is a fundamental property of matter that causes it to experience a force when placed in an electromagnetic field. Charges are of two types: positive and negative. The unit of electric charge in the International System of Units (SI) is the coulomb (C).

Properties of Electric Charge

Quantization: Charge is quantized, meaning it exists in discrete packets rather than being continuous. The smallest unit of charge is the charge of an electron:
$e = 1.602 \times 10^{-19} \, \text{C}$
Conservation: The total electric charge in an isolated system remains constant over time. This principle is known as the law of conservation of charge.
Attraction and Repulsion: Like charges repel each other. Unlike charges attract each other.

Coulomb's Law

The force ( $F$ ) between two point charges can be described by Coulomb's law, which states:

F = k_e \frac{{|q_1 \cdot q_2|}}{{r^2}}

Where:

$F$ is the magnitude of the force between the charges,
$q_1$ and $q_2$ are the amounts of the charges,
$r$ is the distance between the centers of the two charges,
$k_e$ is Coulomb's constant, $k_e \approx 8.988 \times 10^9 \, \mathrm{N \cdot m^2 \cdot C^{-2}}$ .

Conductors and Insulators

Conductors: Materials that allow electric charges to flow freely. Examples include metals like copper and aluminum.
Insulators: Materials that do not permit the free flow of charges. Examples include rubber, glass, and dry wood.

Electric Field

An electric charge creates an electric field ( $\mathbf{E}$ ) around it. The electric field at a point in space is defined as the force ( $\mathbf{F}$ ) per unit charge ( $q$ ) at that point:

\mathbf{E} = \frac{\mathbf{F}}{q}

The direction of the electric field is the direction of the force that a positive test charge would experience.

Understanding these basic aspects of electric charge provides a foundation for further studies in electromagnetism and electrical engineering.