1. Isotopes
Standard C-2: The student will demonstrate an understanding of atomic structure and nuclear processes.

2. ISOTOPES
Isotopes:
An atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons.

3. ISOTOPES There are about 2000 different isotopes that are known.
Of this number, only 279 are stable-they do not change over time.

4. RADIOISOTOPES
Radioisotopes - the nucleus will decay (change) over time and release radiation-energy or particles.
This change is spontaneous-occurs without action/intervention.

5. ISOTOPES
Uranium-238 OR
238 U 92

6. U U Nuclear Symbol Format 238 235 92 92
This uranium atom has 92 protons and 146 neutrons
This uranium atom has 92 protons and 143 neutrons

7. Practice
Find the number of protons and neutrons in each of the following:
228 88 Ra 2. 14 6 C 3.
218 84 Po 1.
Answer on your paper.
The next slide shows the answers.

8. Practice Answers Ra C Po
The number of protons and neutrons in each of the following are:
228
218 14 1. Ra 2. C 3. Po 88 6 84
6 Protons
8 Neutrons
84 Protons
134 Neutrons
88 Protons
140 Neutrons

9. Practice Promethium-142 Lead-214 Polonium-212
Find the number of protons and neutrons for each of the following:
Promethium-142
Lead-214
Polonium-212
Answer on your paper.
The next slide shows the answers.

10. The number of protons and neutrons for each of the following are:
Practice Answers
The number of protons and neutrons for each of the following are:
Promethium-142
Lead-214
Polonium-212
61 Protons 81 Neutrons
82 Protons 132 Neutrons
84 Protons
128 Neutrons