Year :
2013
Title :
Chemistry
Exam :
WASSCE/WAEC MAY/JUNE
Paper 1 | Objectives
1 - 10 of 47 Questions
| # | Question | Ans |
|---|---|---|
| 1. |
Which of the following instruments is used in detecting the presence of radiation? A. Cathode ray tube B. Geiger-Muller counter C. Mass spectrometer D. X-ray tube Detailed SolutionThe Geiger- Muller counter is a device for measuring radioactivity by detecting and counting ionizing particles. |
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| 2. |
The molecule which has a linear shape is A. CH4 B. NH3 C. H2S D. CO2 Detailed SolutionThe shapes of the molecules are:CH\(_4\) - Tetrahedral; NH\(_3\) - Trigonal pyramidal; H\(_2\)S - Bent; C)\(_2\) - Linear. |
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| 3. |
The formula of the compound formed between a trivalent metal, M and a divalent non-metal, Y is A. M2Y3 B. M3Y2 C. MY D. M3Y Detailed SolutionM is a trivalent metal i.e M = 3+ ; Y is a divalent non-metal i.e Y = 2-A reaction between M and Y will yield M\(_2\)Y\(_3\). |
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| 4. |
An atom of an element X gains two electrons. The symbol of the ion formed is A. X + B. X 2+ C. X 2- D. X - Detailed SolutionX gained two electrons. X = 2-.The ion formed is X\(^{2-}\). |
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| 5. |
Which of the following statements is correct? A. Atomic size decreases down the group B. Atomic size increases across the period C. Anions are smaller than the parent atom D. Cations are smaller than the parent atom Detailed SolutionA cation is a positively charged ion. This means electron is given out by a cation, hence the cation is smaller than the parent atom. |
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| 6. |
Which of the following arrangements represents the correct order of electronic energy level? A. 1s 2p 2s 3p 3s 3d 4s B. 1s 2s 2p 3s 3p 3d 4s C. 1s 2s 2p 3s 3p 4s 3d D. 1s 2s 3s 2p 3p 4s 3d |
C |
| 7. |
The element with electron configuration 1s\(^2\) 2s\(^2\) 2p\(^6\) 3s\(^2\) 3p\(^1\) belongs to A. s-block period 3, group 1 B. p-block, period 3, group 2 C. s-block, period 3, group 3 D. p-block, period 3, group 3 Detailed Solution1s\(^2\) 2s\(^2\) 2p\(^6\) 3s\(^2\) 3p\(^1\) = 2, 8, 3.The element is in period 3 and group 3. |
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| 8. |
In the periodic table all elements within the same group have the same A. number of neutrons B. number of valence electrons C. number of isotopes D. atomic number Detailed SolutionThe elements in the same group in the periodic table has the same number of electrons in the outer shell. That means, they have the same number of valence electrons. |
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| 9. |
Which of the following halogens is liquid at room temperature? A. lodine B. Chlorine C. Bromine D. Fluorine Detailed SolutionBromine is a reddish-brown liquid at room temperature. |
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| 10. |
Rare gases are stable because they A. are chemically active B. contain equal number of protons and neutrons C. contain more electrons than protons D. have octet structures Detailed SolutionThey are the most stable due to having the maximum number of valence electrons their outer shell can hold. That means rare gases have the octet configuration. |
| 1. |
Which of the following instruments is used in detecting the presence of radiation? A. Cathode ray tube B. Geiger-Muller counter C. Mass spectrometer D. X-ray tube Detailed SolutionThe Geiger- Muller counter is a device for measuring radioactivity by detecting and counting ionizing particles. |
|
| 2. |
The molecule which has a linear shape is A. CH4 B. NH3 C. H2S D. CO2 Detailed SolutionThe shapes of the molecules are:CH\(_4\) - Tetrahedral; NH\(_3\) - Trigonal pyramidal; H\(_2\)S - Bent; C)\(_2\) - Linear. |
|
| 3. |
The formula of the compound formed between a trivalent metal, M and a divalent non-metal, Y is A. M2Y3 B. M3Y2 C. MY D. M3Y Detailed SolutionM is a trivalent metal i.e M = 3+ ; Y is a divalent non-metal i.e Y = 2-A reaction between M and Y will yield M\(_2\)Y\(_3\). |
|
| 4. |
An atom of an element X gains two electrons. The symbol of the ion formed is A. X + B. X 2+ C. X 2- D. X - Detailed SolutionX gained two electrons. X = 2-.The ion formed is X\(^{2-}\). |
|
| 5. |
Which of the following statements is correct? A. Atomic size decreases down the group B. Atomic size increases across the period C. Anions are smaller than the parent atom D. Cations are smaller than the parent atom Detailed SolutionA cation is a positively charged ion. This means electron is given out by a cation, hence the cation is smaller than the parent atom. |
| 6. |
Which of the following arrangements represents the correct order of electronic energy level? A. 1s 2p 2s 3p 3s 3d 4s B. 1s 2s 2p 3s 3p 3d 4s C. 1s 2s 2p 3s 3p 4s 3d D. 1s 2s 3s 2p 3p 4s 3d |
C |
| 7. |
The element with electron configuration 1s\(^2\) 2s\(^2\) 2p\(^6\) 3s\(^2\) 3p\(^1\) belongs to A. s-block period 3, group 1 B. p-block, period 3, group 2 C. s-block, period 3, group 3 D. p-block, period 3, group 3 Detailed Solution1s\(^2\) 2s\(^2\) 2p\(^6\) 3s\(^2\) 3p\(^1\) = 2, 8, 3.The element is in period 3 and group 3. |
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| 8. |
In the periodic table all elements within the same group have the same A. number of neutrons B. number of valence electrons C. number of isotopes D. atomic number Detailed SolutionThe elements in the same group in the periodic table has the same number of electrons in the outer shell. That means, they have the same number of valence electrons. |
|
| 9. |
Which of the following halogens is liquid at room temperature? A. lodine B. Chlorine C. Bromine D. Fluorine Detailed SolutionBromine is a reddish-brown liquid at room temperature. |
|
| 10. |
Rare gases are stable because they A. are chemically active B. contain equal number of protons and neutrons C. contain more electrons than protons D. have octet structures Detailed SolutionThey are the most stable due to having the maximum number of valence electrons their outer shell can hold. That means rare gases have the octet configuration. |