Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Finding Neutrons in Isotopes
Name:  Joe W.
Status: student
Grade: 9-12
Location:IL
Country: N/A
Date: 5/9/2005


Question:
How do you find neutrons in a Isotope?


Replies:
The usual way is to measure the atomic weight of the element. The number of protons determines the chemical nature of the element. There are a number ways to measure the atomic weight, the most accurate being mass spectrometry, which separates atoms according to their mass number (more precisely mass / charge ratio (m/e)). The difference is the number of neutrons present in the nucleus.

Vince Calder


Joe - subtract atomic number from atomic weight.

The atomic weight of the isotope is the number of protons plus neutrons. The atomic number is the number of protons, period.

So [atomic weight] - [atomic number] = [number of neutrons]

Jim Swenson



Click here to return to the Chemistry Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory