Chemical elements list
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Chemical Elements: Definition and Basic Properties
Chemical elements are the simplest substances that cannot be broken down by chemical means. Each element is made up of atoms with the same number of protons in their nuclei, which defines their atomic number. Elements are represented by unique one- or two-letter symbols and are organized in the periodic table according to their atomic number and recurring chemical properties 15.
Periodic Table of Chemical Elements
The periodic table is a systematic arrangement of all known chemical elements. It displays elements in order of increasing atomic number and groups them based on similar chemical behaviors and electronic configurations. This organization helps to highlight trends in properties such as valence, atomic size, and energy of valence shells. The table also distinguishes between metals (on the left), non-metals (on the right), and metalloids (in between) 1345.
List and Classification of Chemical Elements
There are 118 recognized chemical elements. Of these, 90 occur naturally, while the rest have been synthesized in laboratories. Elements are classified into several groups:
- Alkali metals: Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), Francium (Fr)
- Alkaline earth metals: Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), Radium (Ra)
- Transition metals: Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), and others
- Post-transition metals: Aluminium (Al), Gallium (Ga), Indium (In), Tin (Sn), Thallium (Tl), Lead (Pb), Bismuth (Bi)
- Metalloids: Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), Polonium (Po)
- Non-metals: Hydrogen (H), Carbon (C), Nitrogen (N), Oxygen (O), Phosphorus (P), Sulfur (S), Selenium (Se)
- Halogens: Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At)
- Noble gases: Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn)
- Lanthanides and actinides: Elements in the f-block, such as Lanthanum (La), Cerium (Ce), Uranium (U), Plutonium (Pu), etc. 257
Isotopes and Radioactivity
Some elements have naturally occurring radioactive isotopes, such as carbon-14 (^14C), potassium-40 (^40K), and tritium (^3H). In total, 34 of the 118 elements are radioactive, and some stable elements also have radioactive forms. These isotopes can play important roles in biological and medical processes 57.
Chemical Elements in Biological and Medical Contexts
Many chemical elements are essential for life and play critical roles in biological systems. For example, elements like carbon, hydrogen, oxygen, and nitrogen are fundamental building blocks of biomolecules. Other elements, such as iron, zinc, and magnesium, are vital for enzyme function and cellular processes. Some elements, including certain metals and lanthanides, have biomedical significance and are used in drug development and medical diagnostics .
Educational Tools and Understanding Trends
Modern educational tools, such as online periodic tables, help students learn about the properties and trends of chemical elements more effectively. These tools organize elements by atomic number and properties, making it easier to understand periodic trends and the relationships between different elements 34.
Conclusion
Chemical elements are the foundational substances of chemistry, each defined by its atomic number and unique properties. The periodic table organizes these elements, revealing patterns and trends that are essential for understanding chemical behavior. Elements are not only central to chemistry but also play crucial roles in biology, medicine, and technology, making their study fundamental across scientific disciplines 123457.
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