http://www.ck12.org Chapter 2. Matter
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/54893Q:How do you think the sun is related to protons?
A:The sun’s tremendous energy is the result of proton interactions. In the sun, as well as in other stars, protons from
hydrogen atoms combine, or fuse, to form nuclei of helium atoms. This fusion reaction releases a huge amount of
energy and takes place in nature only at the extremely high temperatures of stars such as the sun.
Identical Protons, Different Elements
All protons are identical. For example, hydrogen protons are exactly the same as protons of helium and all other
elements, or pure substances. However, atoms of different elements have different numbers of protons. In fact,
atoms of any given element have a unique number of protons that is different from the numbers of protons of all
other elements. For example, a hydrogen atom has just one proton, whereas a helium atom has two protons. The
number of protons in an atom determines the electrical charge of the nucleus. The nucleus also contains neutrons,
but they are neutral in charge. The one proton in a hydrogen nucleus, for example, gives it a charge of +1, and the
two protons in a helium nucleus give it a charge of +2. To learn more about the relationship between protons and
elements, go to this URL:
http://www.youtube.com/watch?v=lP57gEWcisY (1:57)
Q:There are six protons in each atom of carbon. What is the electrical charge of a carbon nucleus?
A:The electrical charge of a carbon nucleus is +6.
What Are Protons Made of?
Protons are made of fundamental particles called quarks and gluons. As you can see in theFigure2.55, a proton
contains three quarks (colored circles) and three streams of gluons (wavy white lines). Two of the quarks are
called up quarks (u), and the third quark is called a down quark (d). The gluons carry the strong nuclear force
between quarks, binding them together. This force is needed to overcome the electric force of repulsion between
positive protons. Although protons were discovered almost 100 years ago, the quarks and gluons inside them were
discovered much more recently. Scientists are still learning more about these fundamental particles. You can take
an animated tour of the atom, including protons and their fundamental particles, at this URL: http://education.jlab.or
g/atomtour/index.html.
Summary
- A proton one of three main particles that make up the atom. It is found in the nucleus. It has an electrical
charge of one +1 and a mass of 1 atomic mass unit (amu). - Atoms of any given element have a unique number of protons that is different from the numbers of protons of
all other elements. - Protons consist of fundamental particles called quarks and gluons. Gluons carry the strong nuclear force
between quarks, binding them together.