What conclusion is best supported by the decay chain?
each alpha decay results in an isotope that is slightly more stable than the original isotope.
each beta decay results in an isotope that is slightly more stable than the original isotope.
the atomic number increase caused by two beta decays is the same as the decrease caused by one alpha decay.
the mass number increase caused by two beta decays is the same as the decrease caused by one alpha decay.

Suppose a pair of chemical compounds a and b can react in two different ways: a + b -> c reaction 1 gives product c. a + b -> d reaction 2 gives product d. the following facts are known about the two reactions: . reaction 1 is endothermic and reaction 2 is exothermic. if a reaction vessel is charged (filled) with a and b , then at first d is produced faster than c. use these facts to sketch a qualitative reaction energy diagram for both reactions. note: because these sketches are only qualitative, the energies don? t have to be exact. they only have to have the right relationship to each other. for example, if one energy is less than another, that fact should be clear in your sketch.