Know Nuclear

Science

We all know science is all around us. But what does nuclear have to do with that? For those who have been out of school for awhile – Welcome back to the basics. For the new students – Welcome to Nuclear 101.

Nuclear Basics

Atoms are made up of  protons and neutrons, collectively called nucleons, surrounded by electrons.

Things you need to know:

• The atomic number of an element (Z) is the number of protons in a nucleus. This determines what the element is.
• The mass number of an element (A) is the number of nucleons in a nucleus. The number of neutrons in a nucleus is A-Z.
• Atoms of elements can contain different numbers of neutrons. Different forms are known as isotopes. The nucleus of an isotope is called a nuclide.
• Radioisotopes and radionuclides refer to radioactive forms of elements.
• A particular isotope of an element is defined by giving the name of the element and the mass number of the isotope. An example of this would be uranium-235.

The symbol is used for the nucleus of an element that has the chemical symbol X, a mass number A, and atomic number Z.

QUIZ YOURSELF

Question
The symbol  is used for a particular isotope. If A = 14 and Z = 6,

• How many protons does the isotope have in its nucleus?
• How many neutrons does the isotope have in its nucleus?
• What is the element X?

Answer

• The atomic number Z = 6 so the isotope has 6 protons in its nucleus.
• The number of neutrons in the nucleus of the isotope is A-Z = 14-6 = 8.
• A periodic table shows that the element that has an atomic number 6 is carbon.