Structure of Atom
The atom is the foundational unit of all chemistry. This hub brings together CurlyArrows tutorials, comparisons, definitions, experiments, and Q&As on atomic structure — covering electrons, protons, neutrons, atomic orbitals, electronic configuration, and isotopes. Built for students moving from school chemistry into organic chemistry.
Article
Everything around us—every breath we take, every object we touch, every star in the night sky—is built from atoms, the invisible building blocks of matter.
Learning Objective: To study how the atomic orbitals of an atom are filled, and how the electronic configuration of an atom is written.
Learning Objective: To learn about the different types of orbitals housing electrons in an atom, their visual representation, meaning, and their ene
Learning Objective: To learn about the nature of the electron, an atom's reactive component.
Learning Objective: To learn about the molecular mass and its calculation from atomic weights.
Learning Objective: To learn about the atomic mass number using protons and neutrons.
Learning Objective: To learn about the components of an atom and the importance of proton numbers.
Learning Objective: To learn about the size and composition of an atom.
Learning Objective: To learn about the average atomic mass and how to calculate it from its isotopic mass and natural abundance.
Chemistry Glossary
Groups in chemistry refer to the arrangement of elements of the periodic table into vertical columns.
Periods in chemistry refer to the horizontal rows of elements in the periodic table, which represent all 118 elements across 7 rows.
The outermost electrons of an atom that are mostly involved in bonding reactions are called valence electrons.
An atom has a central, dense, tightly packed nucleus with a diameter of 10-15 m compared to an atom at 10-10 m, a size equivalent t
Molecular mass is the sum of the masses of all the atoms in the molecule, denoted as m.
A molecule is the smallest unit of a chemical substance that still keeps the substance's properties. It forms when two or more atoms bond together by sharing electrons.
The matter is composed of invisible, indivisible, innumerable particles called atoms.
The Average Atomic mass of an element is the weighted average of the atomic masses of all naturally occurring isotopes of an element.
The unit used to describe the mass of an atom is the unified atomic mass unit, symbolized as amu or μ.
The mass number is the total count of the number of protons and neutrons present in the nucleus of an atom, denoted as A.
The Atomic number (symbol Z) uniquely identifies an element and is equal to the number of protons present in the nucleus of an atom.
Isotopes are a group of atoms belonging to an element with the same atomic number but a different mass number.
A Neutron is an uncharged, neutral subatomic particle found in an atom's nucleus, denoted as n or n0.
A proton is one of the subatomic particles found in every atom’s nucleus, denoted as p or p+.
An electron is a negatively charged elementary particle that constitutes an atom, denoted as e- or β-.
Curious Chemist Handbook: Fun Experiments, Big Discoveries
Atoms are so tiny that even a single drop of water contains more atoms than there are stars in the entire universe.
Comparison
| Atomic Number | Mass Number |
|---|
Valence Electrons | Core Electrons |
|---|
Electron | Proton |
|---|
Short Answer Question
An important thing about an atom is that it is made of three main components- pro
Three main components make an atom-protons,
Learning Objective: To study about the electrons and judge its reactivity based on its placement around an atom’s orbital.
numericals
Q) How many valence electrons do the following elements have -
a) Carbon and Silicon
b) Nitrogen and Phosphorus
c) Oxygen and sulfur