Give reasons:
(a) Metals like $Na, K, Ca$ and $Mg$ are never found in their free state in nature.
(b) Iron loses its lustre over time whereas gold does not.

Open in App

Solution

(a) These metals are highly reactive and thus readily react with air and water to form their compounds.
[1 Mark]
(b) Iron moderatley reacts with air to form its oxide. The oxide forms a layer over the iron metal. Hence it loses its lustre over time.
[0.5 Marks]
Gold being quiet unreactive metal does not react with air easily and hence retains its shine.
[0.5 Marks]

Suggest Corrections

Similar questions

Q. Metals like

N a, K, C a

and

M g

are never found in their free state in nature.

Q. Assertion :Metals like Na, K, Ca and Mg are never found in their free state in nature. Reason: Metals are very reactive elements. So, it combine with other non metal to complete its octet. Metals like Na, K, Ca and Mg are never found in their free state in nature.

Question 61
Explain the following:

(a) Reactivity of $Al$ decreases if it is dipped in ${HNO}_{3}$ .
(b) Carbon cannot reduce the oxides of $Na$ or $Mg$ .
(c) $NaCl$ is not a conductor of electricity in the solid state whereas it does conducts electricity in aqueous solution as well as in molten state.
(d) Iron articles are galvanised.
(e) Metals like $Na, K, Ca$ and $Mg$ are never found in their free state in nature.

Q. Mark the correct statement.
a) Metals lose their lustre on keeping in air.
b) Gold is lustrous.
c) Metals are lustrous and can be polished.

Q. Metals at the top of the reactivity series

K, N a, C a

are never found in nature as free elements.

Join BYJU'S Learning Program

Give reasons: (a) Metals like Na, K, Ca and Mg are never found in their free state in nature. (b) Iron loses its lustre over time whereas gold does not.

Give reasons:
(a) Metals like $Na, K, Ca$ and $Mg$ are never found in their free state in nature.
(b) Iron loses its lustre over time whereas gold does not.