Atomic Structure Basics

What is the main component of an atomic nucleus?

Who first proposed that matter is composed of atoms?

What determines the atomic number of an element?

Why do atoms of different elements have different atomic structures?

What is the arrangement of electrons around the nucleus of an atom?

Who proposed the first scientific theory of atomic structure?

What do protons and neutrons make up?

What was a major demerit of Dalton's atomic theory?

What was the main contribution of J.J. Thomson to the field of atomic structure?

What is the main purpose of the vacuum pump in the cathode ray experiment?

What did Dalton suggest about the atoms of an element?

What is the outcome of chemical reactions according to Dalton's atomic theory?

What did Dalton's atomic theory successfully explain?

What is the name of the experiment that J.J. Thomson used to describe his atomic model?

What is the term used to describe the smallest particle responsible for chemical reactions according to Dalton's theory?

Atomic Structure

An atom consists of a nucleus (centre) containing protons (positively charged) and neutrons (neutral), surrounded by negatively charged electrons.
The study of atomic structure provides insight into chemical reactions, bonds, and physical properties.

History of Atomic Structure

Democritus first proposed that matter is composed of atoms.
John Dalton proposed the first scientific theory of atomic structure in the 1800s.

Subatomic Particles

The discovery of subatomic particles has led to many other discoveries and inventions.
The atomic structure of an element is made up of protons, electrons, and neutrons.

Atomic Number and Ions

The atomic number of an element describes the total number of protons in its nucleus.
Neutral atoms have equal numbers of protons and electrons.
Atoms may gain or lose electrons to form ions, increasing their stability.

Atomic Models

Many scientists, including John Dalton, J.J. Thomson, Ernest Rutherford, and Niels Bohr, have contributed to the development of atomic models.
Each model has its own merits and demerits.

Dalton's Atomic Theory

John Dalton suggested that all matter is made up of atoms, which are indivisible and indestructible.
Atoms of different elements differ in size and mass.
Dalton's atomic theory explained the Laws of chemical reactions, including the Law of conservation of mass and the Law of constant properties.

Demerits of Dalton's Atomic Theory

The discovery of particles inside atoms led to a better understanding of chemical species.

Thomson Atomic Model

J.J. Thomson proposed a model describing the atomic structure in the early 1900s.
His work is based on the cathode ray experiment, which led to the discovery of "electrons".

Learn about the fundamental structure of atoms, including the nucleus and subatomic particles, and how it relates to chemical reactions and physical properties. Explore the history of atomic structure theories.