First 40 Elements of the Periodic Table

Vocabulary flashcards summarizing the first 40 chemical elements, including their atomic numbers, masses, representative compounds, and principal applications.

Hydrogen

Atomic #1, mass 1.008 u. Key compounds: H₂O, HCl, NH₃. Uses: rocket fuel (liquid H₂), Haber-Bosch ammonia, hydrogenation.

Helium

Atomic #2, mass 4.0026 u. No stable compounds. Uses: cryogenics, MRI cooling, balloon lifting gas, inert welding atmospheres.

Lithium

Atomic #3, mass 6.94 u. Compounds: Li₂CO₃, LiOH. Uses: Li-ion batteries, mood stabilizers, heat-resistant glass/ceramics.

Beryllium

Atomic #4, mass 9.0122 u. Compounds: BeO, BeCl₂. Uses: lightweight aerospace alloys, X-ray windows, nuclear moderators.

Boron

Atomic #5, mass 10.81 u. Compounds: H₃BO₃, Borax. Uses: borosilicate glass, detergents, insecticides, semiconductor doping.

Carbon

Atomic #6, mass 12.011 u. Compounds/allotropes: CO₂, CH₄, graphite/diamond. Uses: steelmaking, fuels, polymers, abrasives, basis of organic life.

Nitrogen

Atomic #7, mass 14.007 u. Compounds: NH₃, NO₂, N₂O. Uses: fertilizers, explosives, anesthetic gas (N₂O), inert packaging atmospheres.

Oxygen

Atomic #8, mass 15.999 u. Compounds: H₂O, O₃. Uses: respiration/medical O₂, metal smelting, wastewater treatment, rocket oxidizer.

Fluorine

Atomic #9, mass 18.998 u. Compounds: HF, NaF, PTFE. Uses: Teflon production, water fluoridation, UF₆ for uranium enrichment, refrigerants.

Neon

Atomic #10, mass 20.180 u. No stable compounds. Uses: neon lighting, discharge tubes, cryogenic refrigerant blends.

Sodium

Atomic #11, mass 22.990 u. Compounds: NaCl, NaOH, NaHCO₃. Uses: table salt, chemical feedstock, soaps, de-icing, pH control.

Magnesium

Atomic #12, mass 24.305 u. Compounds: MgO, MgSO₄. Uses: lightweight alloys, flares & fireworks, antacids, fertilizers.

Aluminum

Atomic #13, mass 26.982 u. Compounds: Al₂O₃, AlCl₃, Alum. Uses: aircraft frames, cans, foil, catalysts.

Silicon

Atomic #14, mass 28.085 u. Compounds: SiO₂, SiC, silicones. Uses: semiconductors, glass, solar cells, abrasives (carborundum).

Phosphorus

Atomic #15, mass 30.974 u. Compounds: H₃PO₄, P₄O₁₀. Uses: fertilizers (phosphates), matches, detergents, food additives.

Sulfur

Atomic #16, mass 32.06 u. Compounds: H₂SO₄, SO₂, S₈. Uses: sulfuric acid production, vulcanization of rubber, fungicides.

Chlorine

Atomic #17, mass 35.45 u. Compounds: NaCl, HCl, NaOCl. Uses: water disinfection, PVC plastics, solvents, bleach.

Argon

Atomic #18, mass 39.948 u. No stable compounds. Uses: inert welding gas, lighting (incandescent/fluorescent), window insulation.

Potassium

Atomic #19, mass 39.098 u. Compounds: KCl, KNO₃, KOH. Uses: fertilizers (potash), gunpowder, soaps, medical electrolytes.

Calcium

Atomic #20, mass 40.078 u. Compounds: CaCO₃, CaCl₂, Ca(OH)₂. Uses: cement/concrete, dietary supplements, de-icing & drying agent.

Scandium

Atomic #21, mass 44.956 u. Compounds: Sc₂O₃, ScCl₃. Uses: high-strength Al-Sc alloys (aerospace, sports), metal-halide lamps.

Titanium

Atomic #22, mass 47.867 u. Compounds: TiO₂, TiCl₄. Uses: aerospace & biomedical implants, white pigment in paints, sunscreens.

Vanadium

Atomic #23, mass 50.942 u. Compounds: V₂O₅, NH₄VO₃. Uses: high-strength steel alloys, catalysts for sulfuric acid and selective oxidation.

Chromium

Atomic #24, mass 51.996 u. Compounds: Cr₂O₃, Na₂Cr₂O₇. Uses: stainless steel, chrome plating, pigments, leather tanning.

Manganese

Atomic #25, mass 54.938 u. Compounds: MnO₂, KMnO₄. Uses: steel desulfurization, alkaline batteries, oxidizing disinfectant.

Iron

Atomic #26, mass 55.845 u. Compounds: Fe₂O₃, FeSO₄, Fe₃C. Uses: construction steel, machinery, magnets, essential in hemoglobin.

Cobalt

Atomic #27, mass 58.933 u. Compounds: CoCl₂, CoO. Uses: rechargeable batteries, superalloys, blue pigments, radiotherapy (Co-60).

Nickel

Atomic #28, mass 58.693 u. Compounds: NiO, NiCl₂. Uses: stainless steel, electroplating, coins, hydrogenation catalysts.

Copper

Atomic #29, mass 63.546 u. Compounds: CuSO₄·5H₂O, CuO, CuCl₂. Uses: electrical wiring, plumbing, antimicrobial surfaces, coins.

Zinc

Atomic #30, mass 65.38 u. Compounds: ZnO, ZnSO₄, brass alloy. Uses: galvanizing steel, die casting, sunscreens, brass production.

Gallium

Atomic #31, mass 69.723 u. Compounds: GaAs, GaN. Uses: high-speed/optical semiconductors, LEDs, laser diodes, ICs.

Germanium

Atomic #32, mass 72.630 u. Compounds: GeO₂, GeCl₄. Uses: fiber optics, infrared optics, semiconductor devices.

Arsenic

Atomic #33, mass 74.922 u. Compounds: As₂O₃, GaAs. Uses: semiconductors, historic wood preservatives, restricted herbicides (toxic).

Selenium

Atomic #34, mass 78.971 u. Compounds: SeO₂, Na₂SeO₃. Uses: glass decolorizer, photocells/solar, trace nutritional supplements.

Bromine

Atomic #35, mass 79.904 u. Compounds: HBr, NaBr, organobromines. Uses: flame retardants, photography, water treatment.

Krypton

Atomic #36, mass 83.798 u. No stable compounds; excimer KrF* lasers. Uses: high-performance lighting, flash lamps.

Rubidium

Atomic #37, mass 85.468 u. Compounds: RbCl, Rb₂CO₃. Uses: atomic clocks, spectroscopy research, specialty glass.

Strontium

Atomic #38, mass 87.62 u. Compounds: Sr(NO₃)₂, SrCO₃. Uses: red fireworks, signal flares, ferrite magnets, medical imaging (Sr-89).

Yttrium

Atomic #39, mass 88.906 u. Compounds: Y₂O₃, YAG. Uses: phosphors for LEDs/CRTs, YAG lasers, superconductors, ceramics.

Zirconium

Atomic #40, mass 91.224 u. Compounds: ZrO₂, ZrCl₄. Uses: ceramic glazes, nuclear fuel cladding, corrosion-resistant alloys.