Chapter 2: Atomic structure
c
The subatomic particles present in zirconium and hafnium are electrons, neutrons and protons. A beam of protons is fired into an electric field produced by two charged plates, as shown in the diagram.
+ beam of protons –
i
Describe how the beam of protons behaves when it passes through the gap between the charged plates. Explain your answer. ii Describe and explain what happens when a beam of neutrons passes through the gap between the charged plates.
[2] [2]
Total = 7 3 a Describe the structure of an atom, giving details of the subatomic particles present. b Explain the terms atomic number and nucleon number. c Copy and complete the table: Neutral atom
Atomic number
Nucleon number
Mg
12
24
Al
13
27
[6] [2]
Numbers of each subatomic particle present
d Explain why atoms are neutral. e An oxygen atom has 8 protons in its nucleus. Explain why it cannot have 9 protons. f When calculating the relative mass of an atom, the electrons are not used in the calculation. Explain why not.
[2] [1] [1] [1]
Total = 13 4 The symbols below describe two isotopes of the element uranium. 235 92U
238 92U
a State the meaning of the term isotope. b i In what ways are these two isotopes of uranium identical? ii In what ways do they differ? c In a mass spectrometer uranium atoms can be converted to uranium ions, U2+. State the number of electrons present in one U2+ ion.
[1] [2] [2] [1] Total = 6
5 The table below shows the two naturally occurring isotopes of chlorine. a Copy and complete the table. 35 17Cl
37 17Cl
number of protons number of electrons number of neutrons
b The relative atomic mass of chlorine is 35.5. What does this tell you about the relative abundance of the two naturally occurring isotopes of chlorine? c Magnesium chloride contains magnesium ions, Mg2+, and chloride ions, Cl–. i Explain why a magnesium ion is positively charged. ii Explain why a chloride ion has a single negative charge.
[3]
[2] [1] [2] Total = 8
31