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Chromium is a chemical element; it has symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal. [10] Chromium is valued for its high corrosion resistance and hardness.
Naturally occurring chromium (24 Cr) is composed of four stable isotopes; 50 Cr, 52 Cr, 53 Cr, and 54 Cr with 52 Cr being the most abundant (83.789% natural abundance). 50 Cr is suspected of decaying by β + β + to 50 Ti with a half-life of (more than) 1.8×10 17 years.
The TX-17 and 24 were tested as the "Runt" (Castle Romeo shot) device during Operation Castle in 1954. [1] After the successful tests, basic versions of the Mk 17 and 24 were deployed as part of the "Emergency Capability" program. The MK 17/24 bombs were 24 feet 8 inches (7.52 m) long, and 61.4 inches (1.56 m) diameter.
Map of nuclear-armed states of the world NPT -designated nuclear weapon states (China, France, Russia, United Kingdom, United States) Other states with nuclear weapons (India, North Korea, Pakistan) Other states presumed to have nuclear weapons (Israel) NATO or CSTO member nuclear weapons sharing states (Belgium, Germany, Italy, Netherlands, Turkey, Belarus) States formerly possessing nuclear ...
Each distinct atomic number therefore corresponds to a class of atom: these classes are called the chemical elements. [5] The chemical elements are what the periodic table classifies and organizes. Hydrogen is the element with atomic number 1; helium, atomic number 2; lithium, atomic number 3; and so on.
Na, and one each for 24 Na, 26 Na, and 32 Na). 23 Na is the only stable (and the only primordial) isotope. It is considered a monoisotopic element and it has a standard atomic weight of 22.989 769 28 (2). Sodium has two radioactive cosmogenic isotopes (22 Na, with a half-life of 2.6019(6) years; [nb 1] and 24 Na, with a half-life of 14.9560(15) h).
The Mark 24 nuclear bomb was an American thermonuclear bomb design, based on the third American thermonuclear bomb test, Castle Yankee.The Mark 24 bomb was tied as the largest weight and size nuclear bomb ever deployed by the United States, with the same size and weight as the Mark 17 nuclear bomb which used a very similar design concept but unenriched lithium.
Magnesium (12 Mg) naturally occurs in three stable isotopes: 24 Mg, 25 Mg, and 26 Mg. There are 19 radioisotopes that have been discovered, ranging from 18 Mg to 40 Mg (with the exception of 39 Mg). The longest-lived radioisotope is 28 Mg with a half-life of 20.915(9) h.