Subatomic Particles: Videos & Practice Problems

Understanding the fundamental components of an atom is crucial for grasping the basics of chemistry. Atoms are composed of three subatomic particles: neutrons, protons, and electrons. Neutrons and protons, which are approximately equal in mass, are significantly heavier than electrons and are located in the atom's nucleus, accounting for most of an atom's mass. The mass of these particles is measured in atomic mass units (amu) or Daltons (Da), with 1 amu defined as 1/12 the mass of a carbon-12 atom. This unit of measure translates to:

$1.66\times {10}^{-27}\text{kilograms}$

When it comes to charge, protons carry a positive charge (+1), electrons have a negative charge (-1), and neutrons are neutral (0). The actual charge of a proton or electron is:

$\pm 1.60218\times {10}^{-19}\text{coulombs}$

This understanding of the mass and charge of subatomic particles is essential for delving into more complex topics in chemistry, such as electrochemistry and the behavior of atoms in different states and reactions.

Subatomic Particles

The three key subatomic particles—neutrons, protons, and electrons—exhibit distinct differences and similarities in their masses and charges. A crucial term associated with these particles is the atomic mass unit (AMU), which serves as a standard for measuring the relative mass of atoms and subatomic particles. Specifically, 1 AMU is defined as one twelfth the mass of a carbon-12 atom, and it is also equivalent to a Dalton (Da), named after the chemist John Dalton, a foundational figure in the field of chemistry.

For practical conversions, it is essential to remember that 1 AMU equals approximately \(1.66 \times 10^{-27}\) kilograms. This conversion factor allows for the translation between kilograms and AMU. When examining the actual masses of the subatomic particles, neutrons have a mass of approximately \(1.67493 \times 10^{-27}\) kilograms, while protons are slightly lighter at \(1.67262 \times 10^{-27}\) kilograms. In contrast, electrons are significantly lighter, with a mass of about \(0.00091 \times 10^{-27}\) kilograms. This indicates that the majority of an atom's mass is concentrated in its nucleus, where protons and neutrons reside.

When converting these actual masses into relative masses, we find that the relative mass of a neutron is approximately 1.00866 AMU, the proton is about 1.00727 AMU, and the electron is roughly 0.00055 AMU. This reinforces the understanding that neutrons and protons are much heavier than electrons.

In terms of charge, neutrons are neutral, with a relative charge of 0, while protons carry a positive charge of +1, and electrons possess a negative charge of -1. When expressed in coulombs, the actual charge of a proton is approximately \(+1.602 \times 10^{-19}\) coulombs, and the electron has the same magnitude of charge but with a negative sign, resulting in \(-1.602 \times 10^{-19}\) coulombs. This foundational knowledge about the identities and properties of subatomic particles is essential for further studies in chemistry and physics.

Atomic Mass Unit Example

Osmium, recognized as one of the densest elements on Earth, has a mass of 190.23 grams. To convert this mass into atomic mass units (AMU), also known as Daltons, we can utilize dimensional analysis, a systematic method for converting units.

First, we need to convert grams to kilograms. The conversion factor for this step is:

1 kilogram = 1000 grams or 1 kg = 10³ g.

By placing grams in the denominator and kilograms in the numerator, we can cancel out the grams, leaving us with kilograms.

Next, we apply the second conversion factor, which relates kilograms to AMU. The conversion factor states:

1 AMU = 1.66 × 10⁻²⁷ kilograms.

Again, we place kilograms in the denominator and AMU in the numerator to cancel out the kilograms. This allows us to express the mass in AMU.

The calculation proceeds as follows:

First, convert grams to kilograms:

190.23 g × (1 kg / 1000 g) = 0.19023 kg.

Next, convert kilograms to AMU:

0.19023 kg × (1 AMU / 1.66 × 10⁻²⁷ kg) = 1.15 × 10²⁶ AMU.

Thus, the final result indicates that the mass of osmium in atomic mass units is approximately 1.15 × 10²⁶ AMU or Daltons. This conversion process highlights the importance of dimensional analysis in chemistry, allowing for the accurate transformation of units through the use of conversion factors.

For further understanding, reviewing dimensional analysis techniques can enhance your proficiency in handling similar conversion problems.

According to the table above, how many electrons are required to produce a charge of –2.0 C?

• A. 1.3 × 10¹⁹ electrons
• B. 2.0 × 10¹⁹ electrons
• C. 4.2 × 10²⁰ electrons
• D. 8.5 × 10²⁰ electrons

Answer: (A)

If the charge and mass of one proton is 1.60218 x 10^-19 C and 1.673 x 10^-24 g respectively, what is the charge of 378 kg of protons?

• A. 5.24 × 10¹³ C
• B. 9.07 × 10¹⁴ C
• C. 4.11 × 10¹⁵ C
• D. 3.62 × 10¹⁰ C

Answer: (D)

Here’s what students ask on this topic:

What are subatomic particles?

Subatomic particles are the smaller constituents of an atom, which is the basic unit of matter. These particles include protons, neutrons, and electrons. Protons and neutrons form the nucleus at the center of an atom, while electrons orbit around the nucleus in various energy levels.

Protons carry a positive electric charge, and their number in an atom's nucleus defines the chemical element's atomic number. Neutrons have no electric charge and contribute to the mass of an atom; they also play a key role in the stability of the nucleus. Electrons, which are negatively charged, are much lighter than protons or neutrons and are responsible for the chemical properties and reactions of an atom because they are involved in forming chemical bonds.

Beyond these three well-known particles, there are even smaller particles called quarks, which make up protons and neutrons, and leptons, which include the electron and its neutrino. These particles are fundamental in the Standard Model of particle physics, which is the theory describing the electromagnetic, weak, and strong nuclear interactions.

What subatomic particles are found in the nucleus?

The nucleus of an atom contains two types of subatomic particles: protons and neutrons. Protons are positively charged particles, and the number of protons in the nucleus determines the atomic number of an element, which defines the type of element it is. Neutrons, on the other hand, have no electric charge – they are neutral. The presence of neutrons contributes to the atomic mass of the atom and can vary in number among atoms of the same element, leading to the formation of different isotopes. Both protons and neutrons are collectively referred to as nucleons. They are held together in the nucleus by a strong nuclear force, which is much stronger than the electromagnetic force that repels the positively charged protons from each other.

How many subatomic particles are there?

Subatomic particles are the building blocks of atoms and come in various types, primarily categorized as fermions and bosons. Fermions include quarks and leptons, while bosons include force carrier particles like photons and gluons.

Quarks come in six 'flavors': up, down, charm, strange, top, and bottom, and they combine to form protons and neutrons. Leptons include the electron, muon, tau, and their corresponding neutrinos.

Bosons, on the other hand, are particles that mediate the fundamental forces of nature. The photon is the carrier of the electromagnetic force, the W and Z bosons are responsible for the weak force, gluons mediate the strong force, and the Higgs boson is associated with the Higgs field that gives particles mass.

In total, the Standard Model of particle physics identifies 17 fundamental subatomic particles: 6 quarks, 6 leptons, and 5 bosons. However, there are many more composite particles and resonances that arise from combinations of these fundamental particles, such as protons and neutrons (which are made of quarks). Additionally, there may be other subatomic particles not yet discovered that could exist beyond the Standard Model.

What are the three subatomic particles?

The three subatomic particles that form an atom are protons, neutrons, and electrons. Protons are positively charged particles found in the nucleus of an atom. The number of protons in the nucleus determines the atomic number of an element and thus its identity. Neutrons, which are neutral particles with no charge, are also located in the nucleus. They contribute to the mass of the atom and can affect the stability of the nucleus. Electrons are negatively charged particles that orbit the nucleus at various energy levels, often referred to as electron shells or clouds. The interactions between electrons and other atoms play a crucial role in chemical reactions and bonding. The balance between the number of protons and electrons in a neutral atom is equal, resulting in no overall charge.

What are the charges and relative masses of subatomic particles?

Subatomic particles, which are the building blocks of atoms, include protons, neutrons, and electrons. Each type of particle has a distinct charge and relative mass.

Protons carry a positive charge, with a relative charge of +1. Their relative mass is approximately 1 atomic mass unit (amu), which is about $1.6726\times {10}^{-27}\text{kilograms}$.

Neutrons have no electric charge, meaning they are neutral, with a relative charge of 0. They are slightly more massive than protons, with a relative mass close to 1 amu, approximately $1.6749\times {10}^{-27}\text{kilograms}$.

Electrons have a negative charge, with a relative charge of -1. However, they are much lighter than protons and neutrons, with a relative mass of roughly $\frac{1}{1836}$ amu or about $9.1094\times {10}^{-31}\text{kilograms}$.

It's important to note that in the context of atoms, the masses of protons and neutrons are almost equal and significantly larger than the mass of an electron, which is why the bulk of an atom's mass is concentrated in its nucleus, composed of protons and neutrons.