State the number of neutrons in an atom of each of the following isotopes: n (mass number 15) and ni (mass number 58)

:

Atomic number of Nitrogen-15= Number of protons = 7

Mass number = Number of protons + Number of neutrons = 15

Number of neutrons = 15 - 7 = 8

:

Atomic number of Nickel-58= Number of protons = 28

Mass number = Number of protons + Number of neutrons = 58

Number of neutrons = 58 - 28 = 30

The number of neutrons in N-15 is 8 and in Ni-58 is 30

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.