Periodic Table of Elements | Chemical Elements

The Periodic Table of Chemical Elements is one of the most fundamental and important tools in chemistry, first systematically proposed by Russian chemist Dmitri Mendeleev in 1869. It arranges elements by increasing atomic number, placing elements with similar chemical properties in the same vertical columns (groups), revealing the periodic law of element properties as atomic number increases. This page features the first 30 elements, covering categories including nonmetals, alkali metals, alkaline earth metals, transition metals, halogens, and noble gases, providing accurate atomic parameter query services for chemistry learners, teachers, and researchers. Below is a detailed introduction to the core parameters and application scenarios of each element.

⚛️ Detailed Element-by-Element Guide

H Hydrogen — The lightest element and the most abundant in the universe, with atomic number 1, standard atomic weight 1.008, and electron configuration 1s¹. Hydrogen is widely used in ammonia synthesis, petroleum refining, and as a clean energy fuel. It is a colorless, odorless gas at room temperature and highly flammable. Note that hydrogen isotopes deuterium and tritium have important applications in nuclear energy.

He Helium — A colorless, odorless noble gas with atomic number 2, atomic weight 4.0026, and electron configuration 1s². Helium has an extremely low boiling point and is commonly used as a cryogenic coolant, for balloon inflation, and as a protective gas. Due to its extremely inert chemical properties, it hardly participates in any chemical reactions. Note that inhaling helium temporarily changes your voice, but excessive inhalation can cause suffocation.

Li Lithium — The lightest metal element with atomic number 3, atomic weight 6.94, and electron configuration [He]2s¹. Lithium is widely used in lithium batteries, ceramics and glass, lubricating greases, and psychiatric medications. It is soft enough to be cut with a knife. Note that lithium reacts violently with water and must be stored in a dry environment.

Be Beryllium — A lightweight, high-strength alkaline earth metal with atomic number 4, atomic weight 9.0122, and electron configuration [He]2s². Beryllium is commonly used in aerospace alloys, X-ray windows, and as a neutron moderator in nuclear reactors. Note that beryllium and its compounds are highly toxic, requiring strict protection during processing.

B Boron — A black or dark brown metalloid with atomic number 5, atomic weight 10.81, and electron configuration [He]2s²2p¹. Boron is commonly used in borosilicate glass (heat-resistant glass), flame retardants, and semiconductor doping. Boron compounds are used as micronutrient fertilizers in agriculture. Note that elemental boron has extremely high hardness, approaching that of diamond.

C Carbon — The backbone element of organic molecules in living organisms, with atomic number 6, atomic weight 12.011, and electron configuration [He]2s²2p². Carbon exists in various allotropes including graphite, diamond, and fullerenes. It is widely used in steel smelting, organic synthesis, and carbon fiber composites. Note that carbon dioxide is a major greenhouse gas.

N Nitrogen — The main component of air (approximately 78%), with atomic number 7, atomic weight 14.007, and electron configuration [He]2s²2p³. Nitrogen gas is commonly used for food preservation, industrial ammonia synthesis, and as an inert protective gas. Liquid nitrogen plays a crucial role in cryosurgery and biological sample preservation. Note that nitrogen oxides are atmospheric pollutants.

O Oxygen — The most abundant element in the Earth's crust and essential for animal respiration, with atomic number 8, atomic weight 15.999, and electron configuration [He]2s²2p⁴. Oxygen is widely used in steel smelting, medical emergencies, and rocket propellants. The ozone layer absorbs ultraviolet radiation to protect life on Earth. Note that materials burn extremely easily in pure oxygen environments.

F Fluorine — The most electronegative element with atomic number 9, atomic weight 18.998, and electron configuration [He]2s²2p⁵. Fluorides are commonly used in toothpaste for cavity prevention, Teflon coatings, and uranium enrichment. Fluorine gas is a pale yellow, highly toxic gas with extreme corrosiveness. Note that hydrofluoric acid can dissolve glass and must be stored in plastic containers.

Ne Neon — A noble gas with atomic number 10, atomic weight 20.180, and electron configuration [He]2s²2p⁶. Neon gas emits a distinctive orange-red light when electrically charged, widely used in neon advertising signs. It is also used as a high-voltage indicator and low-temperature refrigerant. Note that neon is chemically extremely inert.

Na Sodium — A silvery-white alkali metal with atomic number 11, atomic weight 22.990, and electron configuration [Ne]3s¹. Sodium is commonly used in table salt (sodium chloride), sodium vapor lamps, and as a reducing agent in organic synthesis. It is soft and reacts violently with water to produce hydrogen gas. Note that sodium must be stored in kerosene to isolate it from air.

Mg Magnesium — A lightweight silvery-white alkaline earth metal with atomic number 12, atomic weight 24.305, and electron configuration [Ne]3s². Magnesium alloys are widely used in aerospace and automotive industries, and magnesium powder is used in fireworks and flares. Chlorophyll molecules contain magnesium ions, which are key to photosynthesis. Note that magnesium burns with a brilliant white light.

Al Aluminium — The most abundant metallic element in the Earth's crust, with atomic number 13, atomic weight 26.982, and electron configuration [Ne]3s²3p¹. Aluminium is widely used in construction profiles, food packaging, and power transmission lines due to its lightweight and corrosion resistance. The thermite reaction can be used for welding rails. Note that excessive aluminium ion intake may be harmful to the human nervous system.

Si Silicon — The core material of the semiconductor industry, with atomic number 14, atomic weight 28.085, and electron configuration [Ne]3s²3p². Silicon is widely used in integrated circuit chips, solar cells, and glass manufacturing. Silicon dioxide is the main component of sand and quartz. Note that single-crystal silicon requires extremely high purity to meet chip manufacturing requirements.

P Phosphorus — Exists in several allotropes including white and red phosphorus, with atomic number 15, atomic weight 30.974, and electron configuration [Ne]3s²3p³. Phosphorus is a key component of DNA, ATP, and bones, and phosphate fertilizers are crucial for agricultural production. Note that white phosphorus is highly toxic and flammable, and must be stored under water.

S Sulfur — A yellow nonmetallic solid with atomic number 16, atomic weight 32.06, and electron configuration [Ne]3s²3p⁴. Sulfur is commonly used in rubber vulcanization, sulfuric acid production, and gunpowder formulations. Sulfur hot springs have antibacterial and antipruritic effects. Note that sulfur dioxide is a major cause of acid rain.

Cl Chlorine — A yellow-green irritating gas belonging to the halogens, with atomic number 17, atomic weight 35.45, and electron configuration [Ne]3s²3p⁵. Chlorine is widely used for water disinfection, bleaching agents, and PVC plastic production. Note that chlorine gas was once used as a chemical weapon, and inhaling high concentrations can be fatal.

Ar Argon — The third most abundant gas in air, with atomic number 18, atomic weight 39.948, and electron configuration [Ne]3s²3p⁶. Argon is commonly used as a welding shielding gas due to its inertness, and is also filled in light bulbs to extend filament life. Note that argon is denser than air and can cause suffocation in confined spaces.

K Potassium — A silvery-white alkali metal with atomic number 19, atomic weight 39.098, and electron configuration [Ar]4s¹. Potassium fertilizer is one of the three major agricultural fertilizers, and potassium ions are crucial for nerve signal transmission. Note that potassium reacts violently with water and must be stored in kerosene.

Ca Calcium — The main constituent element of bones and teeth, with atomic number 20, atomic weight 40.078, and electron configuration [Ar]4s². Calcium is widely used in cement, lime, and calcium supplements. Calcium ions play a key role in muscle contraction and blood clotting. Note that quicklime releases heat when in contact with water.