ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
Meeting Spotlight
2021 Student Conference
April 8–10, 2021
Virtual Meeting
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Jan 2021
Jul 2020
Latest Journal Issues
Nuclear Science and Engineering
February 2021
Nuclear Technology
January 2021
Fusion Science and Technology
November 2020
Latest News
Understanding the ITER Project in the context of global Progress on Fusion
(photo: ITER Project gangway assembly)
The promise of hydrogen fusion as a safe, environmentally friendly, and virtually unlimited source of energy has motivated scientists and engineers for decades. For the general public, the pace of fusion research and development may at times appear to be slow. But for those on the inside, who understand both the technological challenges involved and the transformative impact that fusion can bring to human society in terms of the security of the long-term world energy supply, the extended investment is well worth it.
Failure is not an option.
Nuclear science is far-reaching in the fabric of modern life. It can help explain the origins of the universe or how x-rays reveal the bones in your body. In fact, nuclear science is at the heart of so many of the technologies that improve our lives, that it’s easy to take for granted how those technologies came to be. But behind every innovation and discovery in the nuclear fields, is a scientist or engineer researching the atomic nucleus and how to use it to improve our lives.
Look around you. Everything you see, including you, is made of the same stuff—elements. Each of those elements has its own unique characteristics, but all elements are made of atoms—the smallest unit of an element that still has the characteristics of the element.
Scientists used to think there was nothing smaller than an atom.
Today, we know the atom is made of smaller particles, and those are made of even smaller particles.
Atomic Structure
Nucleus
The nucleus is made of protons and neutrons; each has the same mass: 1 amu (atomic mass unit).
Protons and neutrons aren’t exactly alike, though; protons have a positive charge while neutrons don’t have a charge.
Electrons
Electrons are so small that they have nearly no mass at all. A single neutron has only 1/1836 amu. They are also negatively charged.
Organizing the Elements
All of the known elements are organized on the periodic table of the elements. They are arranged by atomic number, from smallest to largest, and labeled with their element symbol, atomic number, and atomic mass.
Standard Nuclear Notation
To easily communicate information about the elements, scientists use standard nuclear notation.
Nuclear notation is formed by writing an elemental symbol preceded by a subscript indicating its atomic number—the number of protons—and a superscript indicating its mass number—the number of protons and neutrons combined.
For example: Carbon has 6 protons, so it’s atomic number is 6.
Carbon's mass number is 12. How many neutrons does it have?
The mass number of an element is a round number; the atomic mass usually isn't. Atomic mass is an average mass of all of the isotopes of an element. We use the mass number, which is always a round number, to make calculations easier.
Isotopes
Think about clover. Clovers can have three, four, or even more leaves. The four-leaved clovers are rare, but they are still clovers. In a similar way, two atoms of an element can have different numbers of neutrons. Because they still have the same number of protons, though, they are the same element. These “varieties” of the same element are called isotopes.
Learn more about radioactivity
Atomic Mass
Last modified December 10, 2020, 2:46pm CST
