H|⚡|Element|Hydrogen gas is used in some fuel cells to make electricity.|The lightest element helps connect chemistry, water and clean-energy research.
He|❄|Element|Liquid helium cools superconducting magnets in many MRI scanners.|It stays liquid at extremely low temperatures and hardly reacts.
Li|▣|Compounds / ions|Lithium ions move between electrodes in rechargeable phone and battery-storage cells.|Its light atoms help batteries store useful energy for their mass.
Be|▤|Element / alloys|Beryllium is used in specialised X-ray windows and light, stiff aerospace parts.|Its low mass and stiffness are useful, but its dust is highly toxic.
B|▥|Compounds|Boron compounds help make heat-resistant borosilicate laboratory glass.|Changing the ingredients of glass changes what it can withstand.
C|✎|Element|Graphite, a form of carbon, is used in pencil cores and battery electrodes.|One element can form very different materials, including graphite and diamond.
N|❄|Element|Liquid nitrogen is used for rapid cooling; nitrogen gas protects food from oxygen.|Nitrogen is also part of proteins, but plants usually take it up in compounds.
O|＋|Element|Oxygen gas is supplied for medical breathing support.|It supports cellular respiration and combustion; these are chemical reactions.
F|▱|Compounds|Fluoride compounds in toothpaste help protect teeth.|Fluoride compounds have very different properties from reactive fluorine gas.
Ne|☷|Element|Neon gas makes the orange-red light in traditional neon signs.|Electricity can make gas atoms emit characteristic colours of light.
Na|♧|Compounds|Sodium chloride is table salt; sodium compounds have many industrial uses.|Reactive sodium metal is very different from sodium ions in salt.
Mg|✦|Element / alloys|Magnesium is used in light alloys and produces bright light in flares.|Low density matters when engineers want lighter components.
Al|▱|Element / alloys|Aluminium is used in drink cans, aircraft structures and power conductors.|A thin oxide layer helps protect this light metal from further corrosion.
Si|▦|Element|High-purity silicon is used in computer chips and most solar cells.|Its electrical behaviour can be controlled to make semiconductor devices.
P|♧|Compounds|Phosphate compounds are used in fertilisers.|Phosphorus is also part of DNA and the molecules cells use to transfer energy.
S|⚗|Compounds|Sulfur is used to make sulfuric acid, a major industrial chemical.|Its chemistry connects fertilisers, batteries and mineral processing.
Cl|≈|Element / compounds|Chlorine and chlorine-releasing compounds are used to disinfect water.|Useful treatment depends on controlled dosing; chlorine gas is hazardous.
Ar|⌁|Element|Argon gas shields hot metal from air during welding.|Low reactivity makes it a useful protective atmosphere.
K|♧|Compounds|Potassium compounds are major ingredients of many fertilisers.|Potassium ions also help nerves and muscles function.
Ca|▰|Compounds|Calcium compounds are used in cement, plaster and lime.|Bones contain calcium compounds, not pieces of calcium metal.
Sc|✈|Alloys|Small amounts of scandium strengthen some specialised aluminium alloys.|A tiny alloying addition can change how a material performs.
Ti|✈|Element / alloys|Titanium alloys are used in aircraft and medical implants.|Strength, low density and corrosion resistance make a useful combination.
V|▣|Compounds / ions|Vanadium ions store energy in vanadium redox-flow batteries.|The ability to change oxidation state supports energy storage.
Cr|▰|Alloys|Chromium helps give stainless steel its corrosion resistance.|A protective chromium-rich surface layer helps steel last.
Mn|▣|Compounds / alloys|Manganese dioxide is used in alkaline batteries; manganese is also used in steel.|The same element can serve different roles in compounds and alloys.
Fe|▰|Alloys|Iron is the main element in steel used for buildings, tools and machines.|Its alloys combine useful strength, availability and cost.
Co|▣|Compounds / alloys|Cobalt compounds are used in some rechargeable battery cathodes.|Its chemistry also helps make heat-resistant alloys and strong magnets.
Ni|▣|Alloys / compounds|Nickel is used in stainless steel and in some battery materials.|It supports corrosion resistance and several energy-storage chemistries.
Cu|⌁|Element|Copper is used in electrical wiring and heat exchangers.|It carries electricity and heat very well.
Zn|▰|Element|Zinc coats steel in galvanising to help prevent rust.|The coating can protect steel even at small scratches.
Ga|▦|Compounds|Gallium nitride is used in efficient power electronics and LEDs.|A compound semiconductor can behave very differently from a metal.
Ge|▦|Element / compounds|Germanium is used in infrared optics and some optical-fibre materials.|Its interaction with light supports communication and sensing.
As|▦|Compounds|Gallium arsenide is used in some specialised semiconductor devices.|Arsenic chemistry has useful roles, but many arsenic compounds are toxic.
Se|▦|Element|Selenium is used in some photoconductors and glass-making processes.|Its response to light helped develop imaging technology.
Br|▱|Compounds|Bromine compounds are used in some flame-retardant materials.|Compound design can change how materials behave in a fire.
Kr|☷|Element|Krypton is used in some lamps and insulated glazing.|A less reactive gas can provide useful optical and thermal properties.
Rb|◷|Element / isotope|Rubidium atoms provide a frequency reference in some atomic clocks.|Atomic energy differences can be used to keep very accurate time.
Sr|✦|Compounds|Strontium salts produce red colours in fireworks.|Atoms and ions can give recognisable colours when excited.
Y|☷|Compounds|Yttrium compounds are used in phosphors and laser crystals.|Rare-earth-related materials can convert energy into useful light.
Zr|▰|Alloys|Zirconium alloys are used for fuel cladding in many nuclear reactors.|Corrosion behaviour and interaction with neutrons both matter in this application.
Nb|⌁|Alloys|Niobium-titanium alloys are used in superconducting magnets.|Some materials carry current without electrical resistance when cold enough.
Mo|▰|Alloys|Molybdenum is added to steels used at high temperatures or in corrosive conditions.|Alloy chemistry can extend the useful life of equipment.
Tc|＋|Isotope / compound|Technetium-99m compounds are used as tracers in medical imaging.|A short-lived radioactive signal can reveal how organs are working.
Ru|⌁|Element / compounds|Ruthenium is used in specialised electrical contacts and catalysts.|Small amounts can alter surface behaviour and chemical reaction rates.
Rh|⚗|Element|Rhodium helps convert nitrogen oxides in vehicle catalytic converters.|Catalysts speed up reactions without being consumed overall.
Pd|⚗|Element|Palladium is used in catalytic converters and industrial catalysts.|Its surface helps reactant molecules change into other substances.
Ag|⌁|Element|Silver is used in electrical contacts, jewellery and reflective coatings.|High conductivity and reflectivity are useful material properties.
Cd|▣|Compounds|Cadmium compounds are used in some specialised batteries and solar cells.|Its useful electronic properties must be managed alongside serious toxicity.
In|▱|Compounds|Indium tin oxide makes transparent conducting coatings in many screens.|A material can let light through and still conduct electricity.
Sn|⌁|Element / alloys|Tin is used in solders and protective coatings.|A low-melting alloy can join electronic components.
Sb|▱|Compounds / alloys|Antimony compounds are used in some flame-retardant systems.|It shows how small ingredients can change a material's behaviour.
Te|▦|Compounds|Cadmium telluride is used in thin-film solar cells.|Compound semiconductors can turn light into electrical energy.
I|＋|Compounds|Iodine compounds are used in antiseptics and iodised salt.|The body needs a small amount of iodine for thyroid hormones.
Xe|☷|Element|Xenon is used in flash lamps and some spacecraft ion thrusters.|The same gas can support light generation and electric propulsion.
Cs|◷|Isotope / element|The transition in caesium-133 atoms defines the SI second.|An atomic property provides a shared reference for time.
Ba|＋|Compound|Barium sulfate is used as a contrast material in some X-ray examinations.|This very insoluble compound behaves differently from soluble, toxic barium salts.
La|▱|Compounds|Lanthanum compounds are used in some optical glasses and catalysts.|The lanthanide series supports many specialised material technologies.
Ce|▱|Compound|Cerium oxide is used for polishing glass.|Surface chemistry can make a powder useful for precision finishing.
Pr|◎|Alloys|Praseodymium is used in some strong permanent magnets.|Rare-earth electronic structures support useful magnetic materials.
Nd|◎|Alloys|Neodymium-iron-boron magnets are used in motors, headphones and wind turbines.|Strong magnets can help make compact electromechanical devices.
Pm|⚗|Isotope / research|Promethium-147 has been used in specialised nuclear batteries and research.|All promethium isotopes are radioactive, limiting everyday uses.
Sm|◎|Alloys|Samarium-cobalt magnets are used where heat resistance matters.|Different magnet alloys suit different operating conditions.
Eu|☷|Compounds|Europium compounds make red light in some display and lighting phosphors.|Electron energy changes can produce specific colours.
Gd|＋|Compounds|Gadolinium-containing chelates are used in some MRI contrast agents.|Carefully designed compounds can make magnetic properties useful in imaging.
Tb|☷|Compounds|Terbium compounds produce green light in some phosphors.|Rare-earth ions help control the colour of emitted light.
Dy|◎|Alloys|Dysprosium is added to some permanent magnets to improve performance when hot.|Temperature behaviour matters as much as room-temperature strength.
Ho|⌁|Compounds|Holmium-doped laser crystals are used in some medical lasers.|Adding selected ions can tune the light a laser produces.
Er|⌁|Compounds|Erbium-doped fibre amplifiers strengthen optical communication signals.|Its optical transitions help light carry information over long distances.
Tm|⌁|Compounds|Thulium-doped materials are used in specialised lasers.|Less common elements can provide specific useful wavelengths.
Yb|⌁|Compounds|Ytterbium-doped fibre lasers are used in industrial processing.|Its electronic structure makes efficient laser materials possible.
Lu|＋|Isotope / compounds|Lutetium-177 compounds are used in some targeted cancer treatments.|A radioactive isotope can deliver radiation to selected tissues.
Hf|▰|Element|Hafnium is used in some nuclear-reactor control rods.|It absorbs neutrons effectively, unlike the chemically similar zirconium.
Ta|▣|Element / oxide|Tantalum and its oxide are used in compact electronic capacitors.|A stable insulating oxide can help store electrical charge.
W|✦|Element|Tungsten is used in high-temperature parts and some lamp filaments.|Its very high melting point makes it useful in extreme heat.
Re|✈|Alloys|Rhenium is used in some high-temperature turbine superalloys.|Very small alloying additions can improve performance in hot engines.
Os|▰|Alloys|Osmium has been used in specialised hard, wear-resistant alloys.|Dense metals can have useful niche roles; some osmium compounds are highly hazardous.
Ir|✦|Element / alloys|Iridium is used in durable spark-plug tips and specialised crucibles.|Resistance to heat and corrosion supports demanding applications.
Pt|⚗|Element|Platinum is used in catalysts, including some fuel cells.|Its surface can help chemical reactions transfer energy efficiently.
Au|⌁|Element|Gold is used on some electronic connectors and in jewellery.|It resists corrosion and makes reliable contact surfaces.
Hg|☷|Element|Mercury has been used in fluorescent lamps and measuring instruments.|Its unusual liquid state is useful, but toxicity has driven replacement in many products.
Tl|▦|Compounds|Thallium compounds are used in some specialised detectors and optical materials.|Niche electronic properties do not remove the need to manage severe toxicity.
Pb|▣|Element / compounds|Lead and lead compounds are used in lead-acid batteries.|A familiar battery chemistry relies on reactions between different lead materials.
Bi|＋|Compounds|Some bismuth compounds are used in medicines for stomach problems.|The properties of a compound depend on its full chemical structure.
Po|⚗|Isotope / specialist|Polonium-210 has been used in specialised static-elimination devices.|Intense radioactivity restricts its use to tightly controlled settings.
At|＋|Isotope / research|Astatine-211 is being studied for targeted cancer therapy.|Very short-lived atoms can still have valuable research roles.
Rn|⚗|Research|Radon is studied in radiation science and environmental monitoring.|It is a naturally occurring radioactive gas and an important indoor health hazard.
Fr|⚗|Research|Francium atoms are studied in atomic-physics experiments.|Its rarity and short half-lives make everyday applications impractical.
Ra|＋|Isotope / medicine|Radium-223 is used in certain cancer treatments.|The isotope, its radiation and its chemical behaviour determine its medical role.
Ac|＋|Isotope / research|Actinium-225 is being investigated and used in targeted alpha-therapy programmes.|Radioactive isotopes can link nuclear physics to medical research.
Th|⚡|Element / research|Thorium is studied as a potential nuclear-fuel resource.|Using it as fuel requires a suitable reactor and fuel cycle.
Pa|⚗|Research|Protactinium is used mainly in scientific research, including isotope studies.|Rare radioactive elements help scientists understand nuclear processes.
U|⚡|Isotopes / compounds|Uranium dioxide containing suitable uranium isotopes is fuel in many nuclear reactors.|Isotope composition matters as well as the element's identity.
Np|⚗|Isotope / specialist|Neptunium-237 can be used as a starting material to make plutonium-238.|Nuclear reactions can turn one element into another.
Pu|⚡|Isotope / compound|Plutonium-238 dioxide supplies heat in some spacecraft power systems.|Radioactive decay can provide long-lasting heat far from the Sun.
Am|⌂|Isotope / compound|Americium-241 oxide is used in some ionisation smoke detectors.|A small radioactive source can help a detector sense smoke.
Cm|⚗|Isotope / research|Curium isotopes are used in research and some alpha-particle instruments.|Radioactive emissions can probe materials and nuclear structure.
Bk|⚗|Isotope / research|Berkelium-249 has been used as a target to create heavier elements.|Making new elements requires carefully chosen target nuclei.
Cf|⚗|Isotope / specialist|Californium-252 is used as a neutron source in specialised instruments.|Some radioactive nuclei release neutrons as they split.
Es|⚗|Research|Einsteinium is made in tiny quantities for studies of heavy-element chemistry.|It tests how familiar chemical patterns hold up in very heavy atoms.
Fm|⚗|Research|Fermium has no everyday commercial use; its isotopes are studied in laboratories.|Its short-lived nuclei help test ideas about nuclear stability.
Md|⚗|Research|Mendelevium is studied a few atoms at a time in heavy-element experiments.|Chemistry can be investigated even with extremely small samples.
No|⚗|Research|Nobelium is used in research on heavy atoms and nuclei.|Its measured ionisation energy helps test atomic calculations.
Lr|⚗|Research|Lawrencium is studied in experiments on the end of the actinide series.|Its electron configuration shows why simple filling rules have exceptions.
Rf|⚗|Research|Rutherfordium is used only in research, including comparisons with zirconium and hafnium.|Experiments test whether family relationships persist in superheavy elements.
Db|⚗|Research|Dubnium is used in laboratory studies of superheavy-element chemistry.|Tiny samples can still reveal chemical similarities and differences.
Sg|⚗|Research|Seaborgium is used in experiments comparing very heavy atoms with lighter group-6 elements.|Relativistic effects become increasingly important for heavy atoms.
Bh|⚗|Research|Bohrium is made for studies of nuclear decay and superheavy chemistry.|Its position suggests relationships that experiments must test.
Hs|⚗|Research|Hassium is used in experiments on very heavy nuclei and chemical behaviour.|The table guides questions even when only a few atoms exist.
Mt|⚗|Research|Meitnerium is made only for nuclear research; no everyday use is known.|Its identity is established even though many properties remain unknown.
Ds|⚗|Research|Darmstadtium is made only in research experiments.|Short lifetimes make many bulk-material measurements impossible.
Rg|⚗|Research|Roentgenium is studied through its production and radioactive decay.|A group position does not guarantee gold-like everyday behaviour.
Cn|⚗|Research|Copernicium is studied in experiments on superheavy atoms.|Very heavy electrons require physics beyond the simplest periodic-trend picture.
Nh|⚗|Research|Nihonium is made in tiny numbers for research on superheavy nuclei.|Confirmed discovery does not mean all chemical properties have been measured.
Fl|⚗|Research|Flerovium is studied in nuclear and atom-at-a-time chemistry experiments.|It helps test predictions about stability and electron behaviour.
Mc|⚗|Research|Moscovium is produced only for scientific research.|Many of its chemical properties remain predictions rather than measurements.
Lv|⚗|Research|Livermorium is made only in studies of superheavy nuclei.|Decay chains help scientists identify extremely short-lived elements.
Ts|⚗|Research|Tennessine is produced only for research; it has no everyday use.|Its group-17 position does not establish all the familiar halogen properties.
Og|⚗|Research|Oganesson is made only for research in extremely small numbers.|Its group-18 position does not prove that it behaves like the lighter noble gases.
