627 articles
All articles — Page 18
Every article in the chemistry library, newest first.
What Is a Base? Alkalis, Hydroxides and Everyday Examples
Bases explained from scratch: how they accept protons, why hydroxide ions matter, the difference between bases and alkalis, their properties, and where you find them at home.
The Neutron: The Uncharged Particle That Holds Nuclei Together
What a neutron is, how James Chadwick discovered it in 1932, why nuclei need neutrons to be stable, how neutron numbers create isotopes, why free neutrons decay, and how neutrons drive nuclear fission, power reactors, date artefacts and probe materials.
The Proton: What It Is and Why It Gives Each Element Its Identity
A guide to the proton: its charge and mass, how Rutherford identified it, why the number of protons defines each element, what holds protons together in the nucleus, quarks inside the proton, protons as hydrogen ions in acid chemistry, and protons in medicine and the Sun.
What Is an Acid? Definitions, Properties and Examples
A clear introduction to acids: what makes a substance acidic, the H⁺ ion, how acids behave, the three definitions chemists use, and the acids you meet every day.
What Is an Atom? A Clear Guide to the Building Block of Matter
A beginner-friendly guide to atoms: what they are, what they're made of, how protons, neutrons and electrons are arranged, why atoms are mostly empty space, how atoms differ between elements, how they join to make everything around us, and how we know they exist.
The Electron: Discovery, Charge, Mass and Why It Matters
Everything a student needs about the electron: J.J. Thomson's cathode-ray discovery, Millikan's oil-drop measurement of its charge, its tiny mass, where electrons are found in atoms, why they control chemical bonding, electricity and light, and how the electron behaves as both a particle and a wave.
What Is Biochemistry?
Biochemistry is the chemistry of living things. Learn what biochemists study, the elements and molecules life is built from, the key ideas that link chemistry to biology, and where biochemistry is used, from medicine to food.
X-ray Fluorescence: Non-destructive Elemental Analysis
How X-ray fluorescence (XRF) identifies elements by knocking out inner electrons and measuring the X-rays emitted, energy-dispersive vs wavelength-dispersive XRF, handheld analysers, and uses in art, archaeology, recycling and mining.
The Zeeman Effect: How Magnetic Fields Split Spectral Lines
Put a glowing gas in a magnetic field and its sharp spectral lines split into several. Learn why the Zeeman effect happens, how big the splitting is, why it revealed electron spin, and how astronomers use it to map sunspots.
Atomic Mass vs. Mass Number vs. Molar Mass: What's the Difference?
Three terms that sound interchangeable but mean genuinely different things — a whole-number count, a weighted average, and a per-mole quantity — explained with real numbers.
What Is the Densest Element? Osmium, Plus the Top 10 Ranked
The densest element is osmium, at about 22.6 g/cm³, only a fraction ahead of iridium. See the top 10 densest elements with real values and why they cluster together.
How to Find the Number of Valence Electrons for Any Element
Read any element's valence electrons from its group number. Includes a valence electrons by group chart, a table for the first 20 elements, and the exceptions.
Ionic vs. Covalent Bonds: What's the Difference?
Why sodium and chlorine give away electrons while two oxygen atoms share theirs — and how to predict which kind of bond a pair of elements will form.
Isotopes vs. Ions vs. Isomers vs. Allotropes: What's the Difference?
Four chemistry terms that all describe a substance changing without becoming a different element or compound — but each one changes something completely different.
The Complete List of Metals, Nonmetals, and Metalloids
Every one of the 118 elements sorted into metal, nonmetal, or metalloid, with the seven metalloids that sit right on the dividing line and why that line is fuzzy.
What Is Molar Mass, and How Do You Calculate It?
What molar mass actually means, why it's central to stoichiometry, and how to calculate it for any formula by hand — plus when to just use a calculator.
Periodic Table Groups and Periods: How to Read the Table
Groups are the 18 columns of the periodic table and periods are the 7 rows. Learn what each tells you about an element, plus blocks, colors and a worked example.
Flame Test Colours: Identifying Metals by the Light They Give Off
The flame test colours of lithium, sodium, potassium, calcium, strontium, barium and copper, why each metal gives a characteristic colour, how to do the test, its limitations, and the chemistry of fireworks.
What Elements Are in the Human Body?
The six elements that make up about 99% of your body mass, the essential minerals and trace elements, what each one does, and why you're mostly oxygen by mass but mostly hydrogen by atoms.
What Are the Largest and Smallest Atoms?
Helium is the smallest atom and cesium or francium the largest, depending on how you measure. Here's why atomic size is tricky to define, the atomic radius trend, and the numbers from our data.
The Most Expensive Elements (and Why They Cost So Much)
Which elements are the most expensive — from synthetic californium to rhodium and gold — why rarity, production difficulty and demand set the price, and why prices swing so much.
Which Element Has the Lowest Melting Point?
Helium has the lowest melting point of any element — and can't freeze at all at normal pressure. Here are the lowest melting points ranked, plus the metals that melt near room temperature.
Which Element Has the Highest Boiling Point?
Rhenium and tungsten have the highest boiling points of any element — above 5,500 °C. See the top 10 ranked from our data, why boiling points peak in the d-block, and the lowest boiling points too.
Which Elements Are Magnetic? Ferromagnetism Explained
Only iron, cobalt, nickel and gadolinium are ferromagnetic at or near room temperature. Here's why, the difference between ferro-, para- and diamagnetism, the Curie temperature, and how rare earths make the strongest magnets.
The Newest Elements: Nihonium, Moscovium, Tennessine and Oganesson
The four elements added to the periodic table in 2016 — nihonium, moscovium, tennessine and oganesson — how they were discovered, where their names come from, and what's next.
What Is the Heaviest Element? Oganesson, Uranium and Osmium
The heaviest element depends on what you mean: oganesson by atomic mass, uranium among natural elements, and osmium by density. Here's how each record-holder compares.
Which Element Has the Highest Melting Point? Carbon, Tungsten and the Top 10
The elements with the highest melting points ranked from our data — carbon, tungsten, rhenium, osmium, tantalum — why carbon's record comes with a catch, and why these metals matter.
What Is the Most Reactive Metal? The Reactivity Series Explained
Why cesium (and in theory francium) is the most reactive metal, how the alkali metals get more reactive down the group, the reactivity series, and what it predicts about displacement and extraction.
The Allotropes of Carbon: Diamond, Graphite, Graphene and Fullerenes
How the same element makes the hardest natural material and one of the softest: the structures and properties of diamond, graphite, graphene, fullerenes, nanotubes and amorphous carbon.
Which Elements Are Gases at Room Temperature? All 11, Explained
The 11 elements that are gases at room temperature — five diatomic gases and six noble gases — where they sit on the periodic table, why they're gases, and what each one is used for.