Problem 21 - Chemistry: The Central Science in SI Units, Global Edition

Question

Answer the following questions without referring to Table 2.1: (a) What are the main subatomic particles that make up the atom? (b) What is the relative charge (in multiples of the electronic charge) of each of the particles? (c) Which of the particles is the most massive? (d) Which is the least massive?

Step-by-Step Solution

Answer

(a) The main subatomic particles that make up the atom are electrons, protons, and neutrons. (b) The relative charge of the particles are: electrons: \(-1\), protons: \(+1\), neutrons: \(0\). (c) Neutrons are the most massive particle. (d) Electrons are the least massive particle.

Step 1: (a) Main Subatomic Particles of the Atom)

The main subatomic particles that make up the atom are electrons, protons, and neutrons.

Step 2: (b) Relative Charge of Each Particle)

The relative charge of the main subatomic particles are as follows: 1. Electrons: -1 (in multiples of the electronic charge) 2. Protons: +1 (in multiples of the electronic charge) 3. Neutrons: 0 (neutral)

Step 3: (c) Most Massive Particle)

Neutrons are the most massive among the three main subatomic particles.

Step 4: (d) Least Massive Particle)

Electrons are the least massive among the three main subatomic particles.

Key Concepts

Atomic Structure

Atoms are the building blocks of all matter. They consist of three main subatomic particles: electrons, protons, and neutrons.
Each of these particles plays a crucial role in the atom's identity and behavior.
Understanding this structure helps us grasp basic principles of chemistry and physics.

• Electrons: These are negatively charged particles that orbit the nucleus of an atom. They are tiny compared to protons and neutrons and move rapidly around the nucleus in various energy levels or shells.
• Protons: Positively charged particles found within the nucleus of an atom. The number of protons determines the atomic number and thus the chemical element of the atom.
• Neutrons: Neutral particles, meaning they have no charge. Neutrons add mass to an atom and are also located in the nucleus.

Together, these particles form a stable structure that defines the atom, with the nucleus housing protons and neutrons, and electrons forming a cloud outside the nucleus.

Electron Charge

The concept of electron charge is fundamental in atomic physics. Each electron carries a charge of e - 1.6 x 10^{-19} C.
This is the unit of negative charge known as the electronic charge.

• Electrons: Each electron has a negative charge, represented as \( -1 \) in terms of relative charge units.
• Protons: Protons have a positive charge equal in magnitude to that of electrons, represented as \( +1 \).
• Neutrons: Neutrons have no charge and are considered neutral.

The charges of these particles are balanced in a neutral atom, where the number of protons equals the number of electrons, resulting in no overall charge.

Particle Mass

Mass is another critical characteristic of subatomic particles. Even though they are incredibly small, their mass helps determine the stability and properties of the atom.
Let's explore the mass of each particle:

• Neutrons: The most massive subatomic particles, neutrons contribute significantly to the atomic mass of an element.
• Protons: Slightly less massive than neutrons, but much more massive than electrons. Protons and neutrons together account for most of an atom’s mass.
• Electrons: Electrons are about 1/1836 the mass of a proton, making them the least massive particle in an atom. They contribute very little to the total atomic mass.

Although particles like electrons contribute minimally to mass, their influence on atomic behavior is substantial, impacting how atoms interact and bond with each other.