Structure of the Atom Worksheet
Which of these' particles exist in the nucleus?
a) proton
b) neutron
c) electron
2. What is a nucleon and where in the atom does it always exist?
3. Which particle in the atom
a) is neutral?
b) is negatively charged?
c) is positively charged'?
d) is much smaller than the others?
e) is, marginally, the largest?
f) is different between isotopes of the same element?
g) always remains the same in isotopes of the same element?
4.
a) What does the atomic number tell you about the number of particles in an atom?
b) What does the nucleon number tell you about the number of particles in an atom?
5. How many protons, neutrons and electrons are there in each of the following neutral atoms
a) 205
81𝑇𝑙
b) 109
47𝐴𝑔
c) 107
47𝐴𝑔
259
d) 102
𝑁𝑜
e) 160
66𝐷𝑦
f) 160
64𝐺𝑑
g) 49𝐵𝑒
h) 238
92𝑈
6. Write in symbol form the following atoms:
a) Oxygen with 8 protons and 8 neutrons
b) Oxygen with 8 protons and 9 neutrons
c) Mercury with 80 protons and 119 neutrons
d) Hydrogen with 1 proton and 1 neutron
e) Nitrogen with 1 proton and 7 neutrons
f) Xenon with 54 protons and 79 neutrons
7. Is oxygen with 8 neutrons or oxygen with 9 neutrons more likely to be stable? Why?
8. In question 6, how many times more heavy is f compared to e?
9. What is an isotope?
10. Complete this table (assume that the atoms are neutral)
Nitrogen atom
Sodium atom
Potassium atom
Uranium atom
Mass number
Atomic number
14
23
39
235
7
Number of
protons
Number of
neutrons
Number of
electrons
11
19
92
11. N/A
12. N/A
13. It has been suggested that some nuclei might decay by a process of double beta decay; this means emitting two
beta particles at the same time. An example is given below. Copy and complete the equation to include the missing
numbers.
82
34𝑆𝑒
→ ??𝐾𝑟 + −10𝛽 + −10𝛽
14. Uranium-238 is found in some rocks. This isotope decays to produce Lead-206.
a) How many alpha particles are emitted in this decay chain?
b) Have any other particles been emitted too?
c) How does radioactivity cause the rocks to warm up?