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To understand the notation and basic quantities involved in nuclear physics

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To understand the notation and basic quantities involved in nuclear physics.

Nuclear physics borrows the symbols for elements from chemistry. However, knowing which element we are dealing with only tells us one of the numbers important to nuclear physics. When referring to a specific nucleus, we use the following notation:

5626Fe.

The superscript, 56 in this case, denotes the total number of nucleons (protons and neutrons) in the nucleus. This is called the nucleon number and is given the symbol A. The subscript, 26 in this case, is the number of protons in the nucleus. This is called the atomic number and is given the symbol Z. An atom's atomic number determines which element the atom is, in this case Fe (iron). Another important number characterizing an atom is the neutron number N. Since A is the total number of nucleons in the nucleus, the neutron number may be found from the equation A=Z+N. Solving for N gives N=A?Z. Nuclei with the same atomic number but different neutron numbers are called isotopes. Isotopes are often written in a form such as "iron-56."

Part A

What is the atomic number Z of 73Li? Express your answer as an integer. (protons).

Part B

What is the nucleon A number of carbon-14? Express your answer as an integer. (Nucleons).

Part C

What is the neutron number N of 5626Fe?

Express your answer as an integer.

N=

(neutrons)

Part D

Which of the following choices lists a pair of isotopes?

	14 6C and 14 7N
	32He and 63Li
	15 7N and 16 8O
	31H and 21H

It has been found that the radii of most nuclei are well approximated by the equation R=R0A13, where R0=1.2?10?15m is an experimentally determined constant. Because the mass of a nucleon (a proton or a neutron) is close to one atomic mass unit (1u), the nucleon number A is sometimes called the mass number.

Part E

What is the approximate radius R of 208 82Pb?

Express your answer in meters to two significant figures.

R=

( m )

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Part F

Assuming that each nucleus is roughly spherical and that its mass is roughly equal to A (in atomic mass units u), what is the density ? of a nucleus with nucleon number A?

Express your answer in terms of A, R0, and ?.

?=

( u/m3)