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PERIODICITY 1 [IB]
1. Which pair of elements reacts most readily?
A. Li + Br2
B. Li + Cl2
C. K + Br2
D. K + Cl2
(Total 1 mark)
2. Explain the following statements.
(a) The first ionization energy of sodium is
(i) less than that of magnesium.
(2)
(ii) greater than that of potassium.
(1)
(b) The electronegativity of chlorine is higher than that of sulfur.
(2)
(Total 5 marks)
3. (i) Explain how the first ionization energy of K compares with that of Na and Ar.
(3)
(ii) Explain the difference between the first ionization energies of Na and Mg.
(4)
(iii) Suggest why much more energy is needed to remove an electron from Na+ than from Mg+.
(1)
(Total 8 marks)
4. Nitrogen is found in period 2 and group 5 of the periodic table.
(i) Distinguish between the terms period and group.
(1)
(ii) State the electron arrangement of nitrogen and explain why it is found in period 2 and group 5 of the periodic table.
(3)
(Total 4 marks)
5. What increases in equal steps of one from left to right in the periodic table for the elements lithium to neon?
A. the number of occupied electron energy levels
B. the number of neutrons in the most common isotope
C. the number of electrons in the atom
D. the atomic mass
(Total 1 mark)
6. The following table shows values that appear in the Data Booklet.
Table 1 Covalent (atomic) radii /10–12 m
|
|
|
|
|
N |
0 |
F |
|
|
|
|
|
70 |
66 |
58 |
|
Na |
Mg |
Al |
Si |
P |
S |
Cl |
|
186 |
160 |
143 |
117 |
110 |
104 |
99 |
|
Table 2 Ionic radii/10–12 m |
||||||
|
|
|
|
|
N3– |
O2– |
F– |
|
|
|
|
|
171 |
146 |
133 |
|
Na+ |
Mg2+ |
Al3+ |
Si4+ |
P3– |
S2– |
Cl– |
|
98 |
65 |
45 |
42 |
212 |
190 |
181 |
Explain why
(i) the magnesium ion is much smaller than the magnesium atom.
(2)
(ii) there is a large increase in ionic radius from silicon to phosphorus.
(2)
(iii) the ionic radius of Na+ is less than that of F–.
(2)
(Total 6 marks)
7. Which properties of period 3 elements increase from sodium to argon?
I. Nuclear charge
II. Atomic radius
III. Electronegativity
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
(Total 1 mark)
8. Which of the physical properties below decrease with increasing atomic number for both the alkali metals and the halogens?
I. Atomic radius
II. Ionization energy
III. Melting point
A. I only
B. II only
C. III only
D. I and III only
(Total 1 mark)
9. Table 8 of the Data Booklet gives the atomic and ionic radii of elements. State and explain the difference between
(i) the atomic radius of nitrogen and oxygen.
(2)
(ii) the atomic radius of nitrogen and phosphorus.
(1)
(iii) the atomic and ionic radius of nitrogen.
(2)
(Total 5 marks)
10. (i) Describe three similarities and one difference in the reactions of lithium and potassium with water.
(4)
(ii) Give an equation for one of these reactions. Suggest a pH value for the resulting solution, and give a reason for your answer.
(3)
(Total 7 marks)
Download notes on periodicity.
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