Atomic Stability Worksheet
Name:
Date:
All elements are formed by atoms that are made up of:
•	A nucleus containing protons and neutrons.
•	Protons: positively (+) charged particles within the nucleus.
•	Neutrons: particles within the nucleus that have no electrical
charge (neutral).
•	Electrons: particles that orbit the nucleus as a cloud and have a
negative (-) charge.
The atoms of radioactive elements have an unstable nucleus. As
the nucleus tries to become stable it releases energy (ionizing radiation) and extra protons or neutrons
in the form of alpha or beta particles.
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An alpha particle is made up of two protons (+2) and two neutrons from the
atom's nucleus. Alpha particles have a positive charge (+2).
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Before a beta particle is released a neutron changes into a proton and an
electron (-1). The proton stays in the nucleus and the electron is released or
ejected from the nucleus in the form of beta particles. Beta particles have a
negative charge (-1).
Collect the materials and follow the directions to learn how the release of alpha and beta particles
changes the structure of an atom.
Materials:
•	10 objects to represent neutrons.
•	10 objects to represent protons.
•	1 object to represent an electron.
1. Create a pretend radioactive nucleus for Element 1 including 5 neutrons (N) and 6 protons (P).
Element 1
2. Demonstrate what happens to Element 1 when the pretend radioactive nucleus emits an alpha
particle and a new element (Element 2) is formed. Then enter the number of neutrons and
protons in the nucleus of Element 2.
Element 1
Element 2:
^ rHA United States	RadTown Radioactive Atom Activity Set	EPA 402-B-19-019
Environmental Protection	'
* * Agency	https://www.EPA.gov/RadTown/Activity-4-Atomic-5tabilitv

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What differences do you observe between the number of protons and neutrons in Element 2 and
Element 1?
3. Return Element 2 to its original form: Element 1 (5 neutrons and 6 protons). Demonstrate what
happens to Element 1 when it emits a beta particle and a new element (Element 3) is formed.
Then enter the number of neutrons and protons in the nucleus of Element 3.
What differences do you observe between the number of protons and neutrons in Element 3 and
Element 1?
4. Every element has a different number of protons. What happens to unstable (radioactive) atoms
when they release an alpha or beta particle and the number of protons change?
5. Observe the changes in the number of protons and neutrons between the two elements below.
Determine whether the examples show the release of an alpha particle or a beta particle. Circle
the correct answer.
Element 1
Element 3
Polonium
Protons: 84
Neutrons: 126
Protons: 82
Neutrons: 124
Barium
Protons: 56
Neutrons: 81
Cesium
Protons: 55
Neutrons: 82
Alpha particle
Beta particle
Alpha particle
Beta particle
vvEPA
United States
Environmental Protection
Agency
RadTown Radioactive Atom Activity Set	EPA 402-B-19-019
https://www.EPA.gov/RadTown/Activitv-4-Atomic-Stability

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