1. A colourless crystalline solid melts below 150oC and dissolves in water to give a solution that does not conduct electricity. The solid may be
A sodium chloride, NaCl
B silicon dioxide, SiO2
C copper, Cu
D glucose, C6H12O6
2. X, Y and Z are three elements with consecutive proton numbers. X has
the lowest proton number and Y is a noble gas. How is a stable compound formed between X and Z ?
A Each atom of X shares a pair of electrons with an atom of Z.
B Each atom of X receives an electron from an atom of Z to form X+Z–.
C Each atom of X gives an electron to an atom of Z to form X–Z+ .
D Each atom of X receives an electron from an atom of Z to form X–Z+ .
3. In which of the following is there no covalent bond?
B aluminium fluoride
C sodium sulfate
D sulfur dioxide
4. The elements X and Y form the compound X2Y. What is the correct electronic arrangement of the atoms of X and Y?
5. Which substance in the table could be hydrogen chloride?
6. When solid iodine is heated, it changes into a purple gas without passing through the liquid state. In this process
A covalent bonds between iodine atoms are broken.
B covalent bonds between iodine molecules are broken.
C ionic forces between iodine atoms are overcome.
D attractive forces between iodine molecules are overcome.
7. The elements T, X and Y have consecutive, increasing atomic numbers. If element T is noble gas, what will be the symbol for the ion of element Y in its compounds?
8. A stable molecule containing atoms of the elements X, Y and Z has the following structure.
9. Which structural feature of graphite best accounts for its use as a lubricant?
A delocalized electrons
B hexagonal arrangement of carbon atoms
C strong covalent bonds within layers
D weak Van der Waals’ forces between layers
10. A substance contains the ions X4+ and Y2-. What is the simplest formula of the compound containing the ion X4+ and Y2-?
11. The equation below shows the reaction between element X and dilute
X (s) + 2HCl (aq) → XCl2(aq) + H2 (g)
Which types of bonding are present in element X and compound XCl2?
12. Elements X and Y are both non-metallic elements in the Periodic Table. Element X combines with carbon to give the structural formula of X=C=X. Element Y combines with hydrogen to give the structural formula of H-Y.
What is the most likely structural formula of the covalent compound X2Y2?