How many neutrons does uranium have?
There are a few different naturally occurring isotopes of
uranium. Isotopes are atoms of the same element with differing
numbers of neutrons so you need to know what isotope you are
However, since I suspect this might be a homework question ;) I
won't come out and give you the answer, but rather, what I would
tell my own students:
If you find uranium on the periodic table of elements, you will see
a number usually at the top of the box. This is the element's
atomic number and corresponds to the number of protons in its
nucleus. At the bottom, you will see a number that has a whole
bunch of digits after the decimal point. This is the element's
average atomic mass on Earth. The mass of an atom equals the sum of
its protons and neutrons. Therefore, you can round the atomic mass
to the nearest whole number, subtract out the number of protons
(atomic number, remember?) and find the number of neutrons in the
most common isotope of that element on Earth.
To show I'm not such a mean teacher, this is a link to the online
periodic table entry for uranium.