You are given a hammer, a battery, a bulb, wires and a switch.
$(a)$ How could you use them to distinguish between samples of metals and non-metals ?
$(b)$ Assess the usefulness of these tests in distinguishing between metals and non-metals.
$(a) $ With the hammer, we can beat the sample and if it can be beaten into thin sheets (that is, it is malleable), then it is a metal otherwise a non-metal. Similarly, we can use the battery, bulb, wires, and a switch to set up a circuit with the sample. If the sample conducts electricity, then it is a metal otherwise a non-metal.
$(b)$ The above tests are useful in distinguishing between metals and non-metals as these are based on the physical properties. No chemical reactions are involved in these tests.
Samples of four metals $A$, $B$, $C$ and $D$ were taken and added to the following solution one by one. The results obtained have been tabulated as follows.
Metal | Iron $(II)$ sulphate | Cooper $(II)$ sulphate | zinc sulphate | Silver nitrate |
$A.$ | No reaction | Displacement | ||
$B.$ | Displacement | No reaction | ||
$C.$ | No reaction | No reaction | No reaction | Displacement |
$D.$ | No reaction | No reaction | No reaction | No reaction |
Use the Table above to answer the following questions about metals $A$, $B$, $C$ and $D$.
$(i)$ Which is the most reactive metal ?
$(ii)$ What would you observe if $B$ is added to a solution of Copper $(II)$ sulphate ?
$(iii)$ Arrange the metals $A$, $B$, $C$ and $D$ in the order of decreasing reactivity.
$(i)$ Write the electron-dot structures for sodium. oxygen and magnesium.
$(ii)$ Show the formation of $Na _{2} O$ and $MgO$ by the transfer of electrons.
$(iii)$ What are the ions present in these compounds ?
Give reasons : Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
What are amphoteric oxides? Give two examples of amphoteric oxides.
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be