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Hydrogen atom. 1 / 2 . Depiction of a hydrogen atom showing the diameter as about twice the Bohr model radius. (Image not to scale) A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral hydrogen atom contains a nucleus of a single positively charged proton and a single negatively charged electron bound to the ...
Isotopes of hydrogen. Hydrogen (1 H) has three naturally occurring isotopes: 1 H, 2 H, and 3 H. 1 H and 2 H are stable, while 3 H has a half-life of 12.32 (2) years. [ 3 ][ nb 1 ] Heavier isotopes also exist; all are synthetic and have a half-life of less than 1 zeptosecond (10 −21 s). [ 4 ][ 5 ] Of these, 5 H is the least stable, while 7 H ...
Hydrogen is a chemical element; it has symbol H and atomic number 1. It is the lightest element and, at standard conditions, is a gas of diatomic molecules with the formula H2, sometimes called dihydrogen, [11] but more commonly called hydrogen gas, molecular hydrogen or simply hydrogen. It is colorless, odorless, [12] non-toxic, and highly ...
A smaller fraction (about four per million) of free neutrons decay in so-called "two-body (neutron) decays", in which a proton, electron and antineutrino are produced as usual, but the electron fails to gain the 13.6 eV necessary energy to escape the proton (the ionization energy of hydrogen), and therefore simply remains bound to it, forming a ...
The only stable nuclides having an odd number of protons and an odd number of neutrons are hydrogen-2, lithium-6, boron-10, nitrogen-14 and (observationally) tantalum-180m. This is because the mass–energy of such atoms is usually higher than that of their neighbors on the same isobaric chain, so most of them are unstable to beta decay .
Deuterium (hydrogen-2, symbol 2H or D, also known as heavy hydrogen) is one of two stable isotopes of hydrogen; the other is protium, or hydrogen-1, 1 H. The deuterium nucleus, called a deuteron, contains one proton and one neutron, whereas the far more common 1 H has no neutrons. Deuterium has a natural abundance in Earth's oceans of about one ...
The neutron number (symbol N) is the number of neutrons in a nuclide. Atomic number (proton number) plus neutron number equals mass number: Z + N = A. The difference between the neutron number and the atomic number is known as the neutron excess: D = N − Z = A − 2Z. Neutron number is not written explicitly in nuclide symbol notation, but ...
There are 41 odd-numbered elements with Z = 1 through 81, of which 39 have stable isotopes (technetium (43 Tc) and promethium (61 Pm) have no stable isotopes). Of these 39 odd Z elements, 30 elements (including hydrogen-1 where 0 neutrons is even) have one stable odd-even isotope, and nine elements: chlorine (17 Cl), potassium (19 K), copper ...