Modified clay can remove herbicide from water

By creating neatly spaced slits in a clay mineral, University of Groningen Professor of Experimental Solid State Physics Petra Rudolf was able to filter water to remove a toxic herbicide. After removing the pollutant by heating ...

New material created to clean up fossil fuel industry

Researchers at the University of Sydney have created a new material that has the potential to reduce CO2 emissions released during the refinement process of crude oil by up to 28 percent.

Chemists unveil the structure of an influenza B protein

A team of MIT chemists has discovered the structure of a key influenza protein, a finding that could help researchers design drugs that block the protein and prevent the virus from spreading.

New electrode design may lead to more powerful batteries

New research by engineers at MIT and elsewhere could lead to batteries that can pack more power per pound and last longer, based on the long-sought goal of using pure lithium metal as one of the battery's two electrodes, ...

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An ion is an atom or molecule where the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge.

Since protons are positively charged and electrons are negatively charged, if there are more electrons than protons, the atom or molecule will be negatively charged. This is called an anion (pronounced /ˈænaɪən/; an-eye-on), from the Greek ἀνά (ana), meaning 'up'.

Conversely, if there are more protons than electrons, the atom or molecule will be positively charged. This is called a cation (pronounced /ˈkætaɪən/; cat-eye-on), from the Greek κατά (kata), meaning 'down'.

An ion consisting of a single atom is called a monatomic ion. If it consists of two or more atoms, it is called a polyatomic ion. Polyatomic ions containing oxygen, such as carbonate and sulfate, are called oxyanions.

When writing the chemical formula for an ion, its charge is written as a superscript '+' or '−' following a number indicating the difference between the number of protons and the number of electrons. The number is omitted if it is equal to 1. For example, the sodium cation is written as Na+, the '+' indicating that it has one less electron than it has protons. The sulfate anion is written as SO42−, the '2−' indicating that it has two more electrons than it has protons.

If an ion contains unpaired electrons, it is called a radical ion. Just like neutral radicals, radical ions are very reactive.

This text uses material from Wikipedia, licensed under CC BY-SA