Near ground-state cooling of 2-D trapped ion crystals

Researchers have been trying to cool macroscopic mechanical oscillators down to their ground state for several decades. Nonetheless, past studies have merely attained the cooling of a few selected vibrational modes of such ...

Mole rats are pain-free, thanks to evolution

African mole rats are insensitive to many kinds of pain. As an international research team led by the MDC's Gary Lewin reports in Science, this characteristic has allowed mole rats to populate new habitats. Thanks to a genetic ...

Physicists 'teleport' logic operation between separated ions

Physicists at the National Institute of Standards and Technology (NIST) have teleported a computer circuit instruction known as a quantum logic operation between two separated ions (electrically charged atoms), showcasing ...

New coating could have big implications for lithium batteries

Building a better lithium-ion battery involves addressing a myriad of factors simultaneously, from keeping the battery's cathode electrically and ionically conductive to making sure that the battery stays safe after many ...

New technique produces longer-lasting lithium batteries

The grand challenge to improve energy storage and increase battery life, while ensuring safe operation, is becoming evermore critical as we become increasingly reliant on this energy source for everything from portable devices ...

Physicists 'flash-freeze' crystal of 150 ions

Physicists at the National Institute of Standards and Technology (NIST) have "flash-frozen" a flat crystal of 150 beryllium ions (electrically charged atoms), opening new possibilities for simulating magnetism at the quantum ...

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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