Silver Cation: Properties, Reactions, Health and Environmental Effects
Silver (Ag) is a white metal, malleable and ductile. It is insoluble in dilute hydrochloric and sulfuric acids but dissolves readily in nitric acid and concentrated sulfuric acid. Silver is almost always monovalent in its compounds, but divalent oxides, sulfur fluoride, and some coordination compounds containing divalent and trivalent silver are known. Although silver does not oxidize when heated, it can be oxidized chemically or electrolytically to form silver oxide or peroxide, a powerful oxidizing
Read MoreUnderstanding Atoms, Elements, and Chemical Bonds
The Atom: Building Block of Matter
The atom is the fundamental unit of matter, consisting of protons, neutrons, and electrons.
Subatomic Particles
- Electron: Mass approximately 10-31 kg. Discovered by J.J. Thomson.
- Proton: Located in the nucleus, with a mass approximately 1840 x 10-31 kg. Discovered by Rutherford in 1919.
- Neutron: Located in the nucleus, with a mass approximately 1840 x 10-31 kg. Discovered by Chadwick in 1932.
Atomic Models
- Thomson Model: Proposed in 1904, suggesting the atom consists
Industrial Chemical Processes and Environmental Technologies
Industrial Processes and Sustainable Technologies
Pesticide Active Ingredient Screening Evolution
Before the 1980s, screening for active ingredients in the pesticide industry involved expensive and time-consuming greenhouse tests requiring large product amounts. However, with the advent of molecular biology in the 1980s and 1990s, these methods declined, replaced by receptor-inhibitor models and pre-designed compounds. Since 1990, ‘sophisticated screening’ methods have become prevalent. These techniques
Read MoreFundamental Chemistry Terms and Definitions
Atomic Mass Unit (amu)
A unit of mass used to express atomic and molecular weights, equal to one-twelfth of the mass of an atom of carbon-12.
Ion
An atom or group of atoms that carries an electric charge.
Mole
The SI unit for the amount of substance, containing approximately 6.022 x 1023 elementary entities (atoms, molecules, ions, etc.).
Molecule
A group of two or more atoms held together by chemical bonds.
Atomic Mass
The mass of an atom, typically expressed in atomic mass units (amu). It is approximately
Read MoreFundamental Chemistry Concepts: Atoms and Bonds
Subatomic Particles Discovery
Electron
Electrons allow electric current conduction in discharge tubes. Discovered by J.J. Thomson (1897), cathode ray particles were identified as negatively charged and possessing very little mass.
Proton
Observed in discharge tubes as rays traveling opposite to cathode rays when using a perforated cathode (canal rays). Discovered by E. Goldstein (1886), canal rays were found to consist of particles with a positive electric charge and a mass approximately 1837 times
Read MorePeriodic Table History and Chemical Bonding Basics
History of the Periodic Table
The classification of elements began in the nineteenth century following their gradual discovery. Initially, the distinction was simply between metals and nonmetals.
- Johan Döbereiner (1817): Introduced the concept of Triads.
- John Newlands (1863): Proposed the Law of Octaves, sorting elements according to mass.
- Lothar Meyer (1869): Sorted elements based on atomic volume.
- Dmitri Mendeleev (1869): Sorted elements based on mass and properties, leaving gaps for undiscovered