Covert 12.3 000 000 000 mi into scientific notation

Which is mostly likely why many scientists reject the cold fusion theory

The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.

How are isotopes of the same chemical element alike? how are they different?