Search results
Results From The WOW.Com Content Network
Aluminium or aluminum (13 Al) has 23 known isotopes from 21 Al to 43 Al and 4 known isomers.Only 27 Al (stable isotope) and 26 Al (radioactive isotope, t 1/2 = 7.2 × 10 5 y) occur naturally, however 27 Al comprises nearly all natural aluminium.
Aluminium (or aluminum in North American English) is a chemical element; it has symbol Al and atomic number 13. Aluminium has a density lower than that of other common metals, about one-third that of steel. It has a great affinity towards oxygen, forming a protective layer of oxide on the surface when exposed to air.
Isotopes are nuclides with the same number of protons but differing numbers of neutrons; that is, they have the same atomic number and are therefore the same chemical element. Isotopes neighbor each other vertically. Examples include carbon-12, carbon-13, and carbon-14 in the table above.
This is a list of chemical elements and their atomic properties, ordered by atomic number (Z).. Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
The effective atomic number Z eff, (sometimes referred to as the effective nuclear charge) of an electron in a multi-electron atom is the number of protons that this electron effectively 'sees' due to screening by inner-shell electrons. It is a measure of the electrostatic interaction between the negatively charged electrons and positively ...
Aluminium-26 can be used to calculate the terrestrial age of meteorites and comets.It is produced in significant quantities in extraterrestrial objects via spallation of silicon alongside beryllium-10, though after falling to Earth, 26 Al production ceases and its abundance relative to other cosmogenic nuclides decreases.
Aluminium (British and IUPAC spellings) or aluminum (North American spelling) combines characteristics of pre- and post-transition metals. Since it has few available electrons for metallic bonding, like its heavier group 13 congeners, it has the characteristic physical properties of a post-transition metal, with longer-than-expected interatomic ...
For other isotopes, the isotopic mass is usually within 0.1 u of the mass number. For example, 35 Cl (17 protons and 18 neutrons) has a mass number of 35 and an isotopic mass of 34.96885. [7] The difference of the actual isotopic mass minus the mass number of an atom is known as the mass excess, [8] which for 35 Cl is –0.03115.