Protons, neutrons, and electrons in atoms | Atomic structure | High school chemistry | Khan Academy

Summary

This script delves into the fundamental building blocks of our world: atoms. It explains that atoms are composed of subatomic particles—protons, neutrons, and electrons—with the nucleus made up of the former two and the latter forming an electron cloud surrounding it. The script highlights the contrasting charges of protons and electrons, which neutralize each other within atoms, and the mass differences, noting that the majority of an atom's mass is concentrated in its nucleus due to the significantly heavier protons and neutrons compared to electrons. The essence is that despite the variety of substances we encounter daily, they all share the same basic subatomic structure.

Takeaways

• 🌐 Everything in our world is composed of atoms, including the air, water, and materials in our cellphones.
• 🏗️ Atoms are the basic units of matter and act as the building blocks for all substances.
• 👀 Atoms consist of even smaller subatomic particles known as protons, neutrons, and electrons.
• 🔬 The nucleus of an atom is at the center and is made up of protons and neutrons.
• ☁️ Surrounding the nucleus is the electron cloud, where electrons are most likely to be found.
• 🔍 The electron cloud can be significantly larger than the nucleus, making up most of the atom's volume.
• ⚡ Protons have a positive charge, while electrons have a negative charge, and neutrons are neutral.
• 🔋 The charges of protons and electrons are equal and opposite, which results in a neutral atom.
• 📊 The mass of protons and neutrons is about one unified atomic mass unit (U), whereas electrons are much lighter at about 0.0005 U.
• ⚖️ The majority of an atom's mass is concentrated in the nucleus due to the heavier protons and neutrons.
• 🌳 Despite the diverse appearances of substances, the atoms that constitute them are universally made of protons, neutrons, and electrons.

Q & A

What are atoms and why are they important?

Atoms are tiny particles that serve as the basic units of matter, acting as the building blocks for everything in our world, from the air we breathe to the materials in our cellphones.

What are the subatomic particles that make up an atom?

An atom is composed of subatomic particles called protons, neutrons, and electrons.

What is the nucleus of an atom and what does it consist of?

The nucleus is the central part of an atom, composed of protons and neutrons.

Where are electrons most likely to be found in an atom?

Electrons are most likely to be found in the electron cloud, which surrounds the nucleus.

How does the size of the electron cloud compare to the nucleus?

The electron cloud can be 100,000 times larger than the nucleus, making up most of the atom's volume.

What is the charge of protons and electrons, and how do they interact?

Protons have a positive charge of one plus, and electrons have a negative charge of one minus. Their equal and opposite charges cancel each other out when paired in atoms.

Are neutrons charged, and if not, what is their role in an atom?

Neutrons have no charge and are neutral. They contribute to the mass of the atom and help to bind the nucleus together.

How is the mass of subatomic particles expressed and what is the mass of protons and neutrons?

The mass of subatomic particles is expressed in unified atomic mass units (U). Protons and neutrons each have a mass of about one U.

What is the mass of an electron compared to a proton or a neutron?

An electron has a mass of about 0.0005 U, which is roughly 2,000 times smaller than that of a proton or a neutron.

Where does most of the mass of an atom reside?

Most of the mass of an atom resides in the nucleus, due to the significantly greater mass of protons and neutrons compared to electrons.

Despite the diversity in appearance, what commonality do all atoms share?

All atoms share the commonality of being composed of the same subatomic particles: protons, neutrons, and electrons.