If anyone knows anything about chemistry do you think you could help me? How do you find the number of neutrons in an atom? no one in biology or physics could help me please some one know!

Question

across · Answer

It's very simple: Get the table of elements.

jamesj · Answer

...and learn how to read it.  The information on the most common isotope and the number of neutrons will be there.

turingtest · Answer

the number of neutrons are usually the same as the atomic number, but not always. some atoms have a few less or extra neutrons and are called "isotopes"

anonymous · Answer

k aint you supposed to like subtrct the mass number from the atomic number or the other way around??

turingtest · Answer

the other way around

jamesj · Answer

@TuringTest: that's simply not true.  Most elements have a most common isotope that does not have the number of neutrons equal to the atomic number.  This is why the periodic table is so important.

@countryboj: look at your periodic table: are there any mass numbers less than atomic numbers, or are they always equal or greater to the atomic number?  And in fact, what is the definition of mass number?

anonymous · Answer

k i think i get it could you like work one out for me like umm what is (Cu)? like find the mass no. and the number of neutrons?

turingtest · Answer

I really thought most elements had the same number of neutrons and protons, but chemistry is not my strong suit, but you can subtract the atomic number from the mass number.

anonymous · Answer

mass number is the at weight rounded to a whole number i think

anonymous · Answer

ok simply - MASS NUMBER - PROTON (ATOMIC) NUMBER = NEUTRON NUMBER

phi · Answer

The atomic number is equal to the number of protons in the nucleus

anonymous · Answer

MASS NUMBER would be the top number at top, and the PROTON NUMBER is the one at the bottom of the element's symbol

anonymous · Answer

is the mass number always bigger than the atomic number?

turingtest · Answer

for copper there are two common isotopes M=63 and M=65
The atomic number is always 29, so sometimes there are 
65-29=36 neutrons or
63-29=64 neutrons

turingtest · Answer

yes, except for hydrogen which has an isotope which has no neutrons at all.

anonymous · Answer

so big number - little number?

anonymous · Answer

in simple terms yeh

anonymous · Answer

k thank ya

turingtest · Answer

look, atoms have protons and neutrons which each contribute mass. Mass number is counting protons+neutrons and atomic number is just counting protons, so the mass number should be biger, eh?

anonymous · Answer

yea thank ya what about hydrogen how many neutrons are in it? 0?

jamesj · Answer

http://education.jlab.org/qa/pen_number.html or this http://www.classzone.com/books/earth_science/terc/content/investigations/es0501/es0501page06.cfm

anonymous · Answer

thank you!