Give reasons : Platinum, gold and silver are used to make jewellery.

Give reasons : Carbonate and sulphide ores are usually converted into oxides during the process of extraction.

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.

Give an example of a metal which

$(i)$ is a liquid at room temperature.

$(ii)$ can be easily cut with a knife.

$(iii)$ is the best conductor of heat.

$(iv)$ is a poor conduct of heat.

A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?

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