What are amphoteric oxides? Give two examples of amphoteric oxides.

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.

Which metals do not corrode easily?

Give reasons: $Sodium$,$potassium$,and $lithium$ are stored under oil.

Samples of four metals $A$,$B$,$C$ and $D$ were taken and added to the following solutions one by one. The results obtained have been tabulated as follows.

Metal	Iron $(II)$ sulphate	Copper $(II)$ sulphate	Zinc sulphate	Silver nitrate
$A$	No reaction	Displacement	No reaction	Displacement
$B$	Displacement	Displacement	No reaction	Displacement
$C$	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.

What are alloys?