Answer:
number of protons: 94
number of neutrons: 145
239
Pu
94
Explanation:
1) The atomic number, Z, of plutonium is Z = 94, i.e plutonium 94 protons
2) Plutoniun-239 is the isotope with mass number 239.
3) Mass number = number of protons + number of neutrons =>
number of neutrons = mass number - number of protons = 239 - 94 = 145
4) The notation requires that you indicate the symbol of the element with the atomic number (number of protons) and the mass number.
You put the mass number as a superscript at the left side of the symbol and the atomic number as subscript to the left of the symbol.
So, in this case the symbol is Pu, the superscript to the left is 239 and the subscript to the left is 94.
239
Pu
94
A method of converting one unit of measurement to another, like liters to milliliters.
Answer: Option (B) is the correct answer.
Explanation:
Isotopes are the substances or species that contain same number of protons but different number of neutrons.
As it is known that atomic number means the total number of protons present in an atom. Hence, this also means that in isotopes atomic number of the species is same.
For example, isotopes of hydrogen are 
, 
, and 
.
Isotopes of only heavier elements are radioactive in nature as they have large difference in the number of protons and neutrons.
Thus, we can conclude that the statement isotopes of the same element have the same atomic number but differ in their atomic masses, is correct.
A Hypothesis.
I Hope This Helps! (^_^)
