I would say D would be the answer
Nitrogen is the N and that is what is the element is the reactant in excess.
Elements are made of only one kind of atom. The molecule is made up of two or more kinds of atoms. There is no physical change that can separate the compounds into more than one kind of substance. This makes a compound a pure substance.
Answer:
10
Explanation:
The 5 will multiply the subscript 2 on the K atoms making it 10
Radioactive isotope, also called radioisotope, radionuclide, or radioactive nuclide, any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays.
