. You are given pieces of iron, copper, aluminium, magnesium and sodium and directed to perform an activity to verify the hardness of different metals. Pick out the correct observation(s).
(a)All metals are very hard
(b)Iron and Magnesium are hard, other metals are soft
(c)Only iron is the hard metal among them
(d)All given metals except sodium are hard.
Answers
Answer:
(i) When sodium, magnesium and copper are left in air, sodium reacts vigorously with oxygen to form sodium oxide, magnesium reacts with oxygen to form magnesium oxide only on heating, whereas copper does not burn in air even on string heating. It reacts only on prolonged heating. This shows that sodium is most reactive, then magnesium and copper is the least reactive among the three.
(ii) Sodium reacts vigorously with cold water to form sodium hydroxide and hydrogen, magnesium does not react cold water but reacts with hot water to form magnesium hydroxide and hydrogen but copper does not react even with steam. This shows that sodium is highly reactive, magnesium is less reactive than sodium and copper is the least reactive among the three.
Answer:
The correct answer of this question is all metals are very hard .
Explanation:
Given - Given pieces of iron, copper, aluminium, magnesium and sodium.
To Find - Write about the correct observation.
The correct option is all metals are very hard.
The greater the amount of valence electrons in an atom, the stronger the metallic bond created by them, and consequently the harder the metal.
Because sodium is an alkali metal with just one electron in its valence shell, it must be the softest of all. It is readily cut with a knife.
Magnesium is harder than sodium because it has two electrons in its valence shell.
Aluminium's valence shell has three electrons. Copper has the most unpaired electrons of any metal.
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