So if a scientist takes a chunk of carbon-10 (which undergoes beta decay), counts the number of carbon-10 atoms inside it, goes to make coffee, and then comes back to count the number of atoms again, she’ll find that the total number of atoms of carbon-10 is now smaller!In their place she’ll find the beta decay product of carbon-10, which is the element boron.A sensitive CCD camera detects the laser induced fluorescence emitted by the atoms held in vacuum.Trapping force and fluorescence detection require the atom to repeatedly scatter photons at a high rate (~10).This is the key to the superior selectivity of ATTA because it only occurs when the laser frequency precisely matches the resonance frequency of a particular atomic transition.Even the small changes in the atomic transition frequency between isotopes of the same element – the so called isotope shifts – are sufficient to perfectly distinguish between the isotopes.This is not true for zeroth- and second-order reactions.
This lesson helps students understand the important notion that neutrons in the nucleus add to an atom's mass.
Prerequisite understanding for this lesson can be found at the 6-8 level, particularly the idea that "atoms of any element are alike but different from atoms of other elements." (4D Structure of Matter (6-8) #1) The ideas in this lesson are essential for building an understanding of the concept that the nucleus of radioactive isotopes spontaneously decays.
Electrically neutral particles (neutrons) in the nucleus add to its mass but do not affect the number of electrons and so have almost no effect on the atom's links to other atoms (its chemical behavior).
This becomes evident when we rearrange the integrated rate law for a first-order reaction (Equation 14.21) to produce the following equation: Figure \(\Page Index\): The Half-Life of a First-Order Reaction.
This plot shows the concentration of the reactant in a first-order reaction as a function of time and identifies a series of half-lives, intervals in which the reactant concentration decreases by a factor of 2.