The online atom simulations on this page allow us to visualize what the structure of an atom is like, what an isotope is and some of the atomic models that have had the most historical importance.
An atom is the fundamental unit of matter. It is composed of a central nucleus, which contains protons and neutrons, and electrons that orbit around the nucleus. Protons have a positive charge, electrons have a negative charge, and neutrons have no electric charge.
The number of protons in an atom determines its atomic number, which in turn defines the chemical element to which it belongs. For example, hydrogen has one proton, while oxygen has eight. Electrons are distributed in different energy levels called electron shells.
Atoms can combine with each other to form molecules through chemical bonds. This occurs when the electrons of the atoms interact, sharing or transferring electrons with each other. Different combinations of elements and their bonds give rise to a wide variety of chemical substances and compounds.
The structure of an atom is based on the model of quantum mechanics, which describes the behavior of subatomic particles. According to this model, electrons do not move in defined orbits, but are found in regions of increased probability of encountering them, known as orbitals.
The understanding of the atom has led to the development of various technological applications. For example, nuclear energy is based on the fission or fusion of atomic nuclei to generate electricity. In addition, advances in semiconductor technology have enabled the creation of ever smaller and more powerful electronic devices, such as computers and smartphones.
Scientific research continues to explore the secrets of the atom. Particle accelerators and particle physics experiments seek to unravel the fundamental nature of matter and the universe. Understanding the atom is fundamental to our understanding of the world around us and to the development of new technologies that will improve our quality of life.
Build an atom
Build an atom with protons, neutrons and electrons, and see how the element, charge and mass change, then play to test your ideas!
File
Build a nucleus
Build a nucleus with protons and neutrons. See how different disintegrations change the nucleus. Study isotopes and much more!
Ficha
Estructura de un átomo
What does an atom look like? Atomic models are representative “pictures” that help us understand what an atom looks like. Historically, there have been many atomic models.
Electrons configuration
The electrons configuration of an atom refers to the arrangement of the atom’s electrons. The electrons fill the lowest energy levels first.
Bohr’s atomic model
In Bohr’s atomic model the electrons are placed in stable circular orbits around the nucleus. The atom has only certain energy levels. Electrons change energy levels by emitting or absorbing photons.
Atomic interactions
Explore the interactions between various combinations of two atoms. Observe the total force acting on the atoms or the attractive or repulsive force separately. Customize the attraction to see how the interaction is affected by changing the atomic diameter and interaction strength.
File
Isotopes and atomic mass
Are all atoms of an element the same? How can you tell one isotope from another? Use the simulator to learn about isotopes and how abundance relates to the average atomic mass of an element.
File
Pre-University Chemistry
Big Bang and the Origin of Chemical Elements
Preparing for CLEP Chemistry: Part 1
The Physics of Electronic Polymers (PEP)
Energy to Electrochemistry Final Exam
Electrochemistry
Antarctica: From Geology to Human History
Data Science: Linear Regression
Electrotechnique I
Chemical Thermodynamics II: Equilibrium and Kinetics
Groundwater Cycle
Microstructural Evolution of Materials Part 1: Statistical Mechanics
Landscape Ecology
Advanced Fluid Mechanics 1: Fundamentals
