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Atomic Structure
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Atomic Structure 8. What is the structure of the ion 38 Sr 2  ?
1. The letters X, Y and Z represent different atoms. protons neutrons electrons
40 39 40 A 38 52 36
19 X 19 Y 20 Z
B 38 52 38
What can be deduced from the proton numbers and nucleon numbers of X, C 38 90 36
Y and Z? D 52 38 36
A X and Y are the same element. s07/q6
B X and Z are the same element. 9. A researcher notices that atoms of an element X are releasing energy.
C X has more protons than Y. Why does this happen?
D Z has more neutrons than Y. A The atoms are affected by light.
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B The atoms are radioactive.
2. Which of the following contains the same number of electrons as an C The atoms react with argon in the air.
atom of neon? D The atoms are evaporating.
A Cl– B Li C Li+ D O2– w03/q5
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3. An element X has two isotopes, X and X. 238 235 10. An atom of element X is represented by 73 X .
How does 238X differ from 235X? Which statement about an atom of X is correct?
A It has 3 more protons and 3 more electrons. A It is in Group III of the Periodic Table.
B It has 3 more protons, but no more electrons. B It is in Group VII of the Periodic Table.
C It has 3 more neutrons and 3 more electrons. C The total number of protons and electrons is 6.
D It has 3 more neutrons, but no more electrons. D The total number of protons and neutrons is 10.
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4. The formulae of the ions of four elements are shown below. 11. Two particles X and Y have the composition shown in the table.
O2– F– Li+ Mg2+ number of number of number of
Which statement about these ions is correct? particle
electrons neutrons protons
They all have X 10 8 8
A the same number of electrons in their outer shells. Y 18 18 17
B the same electronic structure as a noble gas. The particles X and Y are
C the same number of protons in their nuclei. A metal atoms B non-metal atoms C negative ions D positive ions.
D more electrons than protons. w04/q6
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5. Which statement about all the noble gases is correct? 12. What is the nucleon number of the isotope of uranium, 235
92 U ?

A The number of protons in the atoms equals the number of neutrons. A 92 B 143 C 235 D 327
B Their atoms each have a stable arrangement of electrons. w04/q7
31 32
C Their atoms each have eight electrons in their outer shell. 13. The atoms P15 , 16 P have the same
D They exist as molecules containing two atoms. A nucleon number B number of electrons
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+ – C number of neutrons D number of protons
6. Hydrogen can form both H ions and H ions. w05/q6
Which statement about these two ions is correct? 14.A
A beam of particles contains neutrons, n, protons, p, and
A An H+ ion has no electrons in its first shell. electrons, e. The beam is passed between charged plates.
B An H+ ion has more protons than an H– ion. Which diagram shows how the particles are affected by the plates?
C An H– ion has one more electron than an H+ ion.
D An H– ion is formed when a hydrogen atom loses an electron.
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7. Which graph shows the number of electrons in the outer shell of an
atom, plotted against the proton (atomic) number for the first ten elements
in the Periodic Table?
A B
10 10
8 8
number of 6 number of 6
electrons in electrons in
outer shell 4 outer shell 4
2 2
0 0
0 2 4 6 8 10 0 2 4 6 8 10
proton number proton number
C D
10 10
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8 8 15.Which
Which statement is correct about sulphur, atomic number 16?
number of 6 number of 6 A Sulphur can form the ion S2–.
electrons in electrons in
outer shell 4 outer shell 4 B Sulphur dissolves in water to form sulphuric acid.
2 2 C Sulphur forms ionic oxides.
0 0 D Sulphur will react with metals to produce S6+ ions.
0 2 4 6 8 10 0 2 4 6 8 10 w07/q6
proton number proton number
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