Isotopes are variants of a particular chemical element which differ in neutron
number. .... The existence of isotopes was first suggested in 1913 by the
radiochemist ... F. W. Aston subsequently dis...
Dec 12, 2016 ... Evidence for the existence of isotopes emerged from two ... ores of the
radioactive elements uranium and thorium had been found to contain ...
Due to their high levels of radioactivity, they exist only for extremely short periods
of time. ... The discovery of these particles, integral to the formation of isotopes, ...
Nearly all elements found in nature are mixtures of several different isotopes. ... it
has been possible to find out how much of each isotope exists in each element, ...
Isotopes exist because the atomic nuclei of many elements are stable or
somewhat ... Most radioactive isotopes are so unstable that they are not found in
An isotope is one of two or more species of atoms of a chemical element with the
... that isotopy might exist in the main group of naturally occurring stable elements
. ... This success was followed by the discovery that chlorine had two isotopes.
To express this newly discovered complexity of matter, the terms "isotopic ... That
paper summarized good evidence for the existence of isotopes among ...
For instance, a small amount of carbon exists in the atmosphere as radioactive
carbon-14, and the amount of carbon-14 found in fossils allows paleontologists to
May 13, 2016 ... These basic elements were not generally considered to exist as the actual ... Five
more were discovered through the 17th Century. ..... For example, there are three
natural isotopes of magnesium: <sup>24</sup>Mg (79% of all Mg atoms), ...
Technetium's properties, discovery, videos, images, states, energies, appearance
... Technetium was once thought to exist only in samples produced in the
laboratory. .... It is surrounded in the periodic table by elements with stable