Question

a. What is the nucleus of an atom? b. Who is credited with the discovery of the atomic nucleus? c. Identify the two kinds of particles that make up the nucleus.

Short answer

a. The nucleus is the dense core of an atom. b. Ernest Rutherford. c. Protons and neutrons.

Step-by-step solution

- Definition of the Nucleus

The nucleus is the central part of an atom. It is a dense region composed of protons and neutrons and is the core around which the rest of the atom is structured.

- Discovery of the Atomic Nucleus

The atomic nucleus was discovered by Ernest Rutherford in 1911 through his famous gold foil experiment. His observations helped recognize the nucleus as the core of the atom.

- Particles in the Nucleus

The nucleus is made up of two kinds of particles: protons and neutrons. Protons have a positive electric charge, while neutrons are neutral, having no charge.

Key concepts

nucleus of an atom

The nucleus is the centerpiece of an atom, residing at its core. This central region is incredibly dense and tiny compared to the entire atom. The rest of the atom's structure, including the electrons, revolves around this core. The nucleus is where most of the atom's mass is concentrated. Its small size can be challenging to imagine, but if an atom were the size of a football stadium, the nucleus would be the size of a marble floating in the middle.

protons and neutrons

The nucleus is composed of two types of particles: protons and neutrons.

Protons have a positive electric charge, which is why they play a crucial role in the chemical identity of an element. The number of protons in the nucleus is called the atomic number, and it defines the element—it’s what makes carbon different from oxygen.

Neutrons, on the other hand, are neutral, meaning they have no electric charge. Neutrons add mass to the nucleus and contribute to the stability of the atom. Together, protons and neutrons are known as nucleons. The balance between these particles determines many properties of the atom, including its stability and how it behaves in nuclear reactions.

Ernest Rutherford

Ernest Rutherford, often called the father of nuclear physics, is credited with the discovery of the atomic nucleus in 1911. He made this groundbreaking discovery through his famous gold foil experiment.

In the experiment, Rutherford directed a stream of alpha particles (which are positively charged) at a thin sheet of gold foil. Most particles passed through, but some were deflected at sharp angles. This led Rutherford to propose that atoms have a small, dense nucleus where all its positive charge and most of its mass are concentrated. His discovery was revolutionary and changed our understanding of atomic structure forever.