Year :
2012
Title :
Chemistry
Exam :
WASSCE/WAEC MAY/JUNE
Paper 1 | Objectives
1 - 10 of 44 Questions
| # | Question | Ans |
|---|---|---|
| 1. |
The number of orbitals in a p-sub level of an atom is A. 2 B. 3 C. 5 D. 6 Detailed SolutionThe p- orbital has 3 subshells; P\(_x\), P\(_y\) and P\(_z\) subshells. |
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| 2. |
Which of the following electron configurations represents that of an atom in its ground state? A. 1s 22s12p1 B. 1s22s22p63s13p1 C. 1s22s12p3 D. 1s22s22p63s0 Detailed SolutionThe ground state of an electron, the energy level it normally occupies, is the state of lowest energy for that electron. |
|
| 3. |
Which of the following ions has an electron configuration different from the other? A. 17CI- B. 8O2- C. 12Mg2+ D. 13AI3+ Detailed Solution\(_{17}\)Cl\(^-\) = 18 electrons = 2, 8, 8\(_{12}\)Mg\(^{2+}\), \(_{8}\)O\(^{2-}\) and \(_{13}\)Al\(^{3+}\) all have 10 electrons = 2, 8. |
|
| 4. |
The atomic radii of metals are usually A. greater than their ionic radii B. equal to their ionic radii C. less than their ionic radii D. less than those of non-metals in the same period Detailed SolutionMetals give off electrons. This means that atomic radius is always greater than the ionic radius for metals. |
|
| 5. |
Two elements, X and Y are in the same group on the periodic table because they both have the same A. number of electronic shells B. number of valence electrons C. atomic size D. atomic number Detailed SolutionThe members of the same group always have the same number of electrons in the outer shell (i.e number of valence electrons). |
|
| 6. |
The d-block elements are paramagnetic because they A. contain paired electrons which are repelled by magnetic field B. contain unpaired electrons in the partially filled 3d-orbital C. contain paired electrons which are repelled by magnetic field force D. have delocalized valence electrons Detailed SolutionParamagnetism is a characteristic possessed by an atom with an unpaired electron. |
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| 7. |
Which of the following statements about a radioactive substance is/are correct? l. lt emits radiation continuously and spontaneously. ll. The emitted radiations are affected by temperature and pressure III. The radiation can penetrate opaque matter A. ll only B. l and ll only C. l and lll only D. ll and lll only Detailed SolutionThe properties of radioactive elements holds true except that radioactive decay is not dependent on external conditions except electron capture and bombarding the radioactive material with subatomic particles. |
|
| 8. |
Which of the following elements is a metalloid? A. Carbon B. Oxygen C. Silicon D. Sodium Detailed SolutionSome examples of metalloids include boron, silicon, germanium, arsenic etc. |
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| 9. |
Which of the following halogens is liquid at room temperature? A. Chlorine B. Fluorine C. lodine D. Bromine Detailed SolutionBromine is the third lightest halogen. It is a fuming red-brown liquid at room temperature. |
|
| 10. |
The shape of a graphite crystal is A. tetrahedral B. pyramidal C. hexagonal D. octahedral Detailed SolutionGraphite is a crystalline form of the element Carbon. The atoms are arranged in a hexagonal structure. |
| 1. |
The number of orbitals in a p-sub level of an atom is A. 2 B. 3 C. 5 D. 6 Detailed SolutionThe p- orbital has 3 subshells; P\(_x\), P\(_y\) and P\(_z\) subshells. |
|
| 2. |
Which of the following electron configurations represents that of an atom in its ground state? A. 1s 22s12p1 B. 1s22s22p63s13p1 C. 1s22s12p3 D. 1s22s22p63s0 Detailed SolutionThe ground state of an electron, the energy level it normally occupies, is the state of lowest energy for that electron. |
|
| 3. |
Which of the following ions has an electron configuration different from the other? A. 17CI- B. 8O2- C. 12Mg2+ D. 13AI3+ Detailed Solution\(_{17}\)Cl\(^-\) = 18 electrons = 2, 8, 8\(_{12}\)Mg\(^{2+}\), \(_{8}\)O\(^{2-}\) and \(_{13}\)Al\(^{3+}\) all have 10 electrons = 2, 8. |
|
| 4. |
The atomic radii of metals are usually A. greater than their ionic radii B. equal to their ionic radii C. less than their ionic radii D. less than those of non-metals in the same period Detailed SolutionMetals give off electrons. This means that atomic radius is always greater than the ionic radius for metals. |
|
| 5. |
Two elements, X and Y are in the same group on the periodic table because they both have the same A. number of electronic shells B. number of valence electrons C. atomic size D. atomic number Detailed SolutionThe members of the same group always have the same number of electrons in the outer shell (i.e number of valence electrons). |
| 6. |
The d-block elements are paramagnetic because they A. contain paired electrons which are repelled by magnetic field B. contain unpaired electrons in the partially filled 3d-orbital C. contain paired electrons which are repelled by magnetic field force D. have delocalized valence electrons Detailed SolutionParamagnetism is a characteristic possessed by an atom with an unpaired electron. |
|
| 7. |
Which of the following statements about a radioactive substance is/are correct? l. lt emits radiation continuously and spontaneously. ll. The emitted radiations are affected by temperature and pressure III. The radiation can penetrate opaque matter A. ll only B. l and ll only C. l and lll only D. ll and lll only Detailed SolutionThe properties of radioactive elements holds true except that radioactive decay is not dependent on external conditions except electron capture and bombarding the radioactive material with subatomic particles. |
|
| 8. |
Which of the following elements is a metalloid? A. Carbon B. Oxygen C. Silicon D. Sodium Detailed SolutionSome examples of metalloids include boron, silicon, germanium, arsenic etc. |
|
| 9. |
Which of the following halogens is liquid at room temperature? A. Chlorine B. Fluorine C. lodine D. Bromine Detailed SolutionBromine is the third lightest halogen. It is a fuming red-brown liquid at room temperature. |
|
| 10. |
The shape of a graphite crystal is A. tetrahedral B. pyramidal C. hexagonal D. octahedral Detailed SolutionGraphite is a crystalline form of the element Carbon. The atoms are arranged in a hexagonal structure. |