Name _______________________________________ Period ____
How isotopes are represented.
These are three common ways isotopes are listed.
The mass number is 238.
The atomic number is 92.
The symbol for Uranium is U.
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1. What is the name of the element shown above?
____________
2. What is the atomic number of the element?
____________
3. What is the mass number of the element?
____________
4. The element has how many protons in its nucleus?
____________
5. The element has how many neutrons in its nucleus?
____________
-----------------------------------------------------------------------------------------------------------Alpha decay
 Loss of two protons & two neutrons
 Mass number decreases by 4; atomic number decreases by two
Beta decay
 Neutron in nucleus converted to a proton and an electron; electron given off
 Mass number does not change; atomic number increases by one
Gamma decay
 Given off in association with other types of decay
 Electromagnetic radiation of the highest frequency and energy
 Neither mass number nor atomic number change
-----------------------------------------------------------------------------------------------------------6. The atomic number of element X is 110.
a) What would be the atomic number of element X if it gave off an alpha particle?
_________
b) What would be the atomic number of element X if it gave off a beta particle?
_________
c) What would be the atomic number of element X if it only gave off gamma rays?
_________
7. An atom of element X has a mass of 250 mass units.
a) What would be the mass number of element X if it gave off an alpha particle?
_________
b) What would be the mass number of element X if it gave off a beta particle?
_________
c) What would be the mass number of element X if it only gave off gamma rays?
_________
-----------------------------------------------------------------------------------------------------------8. What is the mass number of
15. What is the mass number of
Polonium-210?
Bismuth-214?
_________________________________
9. What is the atomic number of
Polonium-210?
______________________________
16. What is the atomic number of
Bismuth-214?
_________________________________
10. What is the correct symbol
for Polonium-210?
______________________________
17. What is the correct symbol
For Bismuth-214?
_________________________________
______________________________
Polonium-210 undergoes alpha decay.
Bismuth-214 undergoes beta decay.
11. What is the mass number of the
new isotope?
18. What is the mass number of the
new isotope?
_________________________________
12. What is the atomic number of the
new isotope?
______________________________
19. What is the atomic number of the
new isotope?
_________________________________
13. What is the symbol for the new isotope?
_________________________________
14. What is the name of the new isotope?
_________________________________
______________________________
20. What is the symbol for the new isotope?
______________________________
21. What is the name of the new isotope?
_________________________________