Question

The oxides of period 3 elements are given below



(Na2O, MgO) (Al2O3) (SO2,P2O5)

A B C

a) State two characteristics of these oxides grouped as A,B and C.

b) Name two metals that can be cut with a knife.

c) Give reasons.

i) Non-metals do not form positively charged ions.

ii) Hydrogen gas is not evolved when a metal reacts with nitric acid​

Answer 1

Answer:

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a) A

Na2O, MgO

Metal oxide

B

Al2O3

Amphoteric oxide

C

SO2,P2O5

Acidic oxide

b) Sodium and Potassium metals are the two metals which are soft and can be cut with a knife.

Give reasons :-

i) Non metal has the tendency for gaining the electrons.

They do not get the proton that means the positively charged ion. On the other hand, metals lose the valence electrons to form the cations to get the completely stable octet.

ii) Hydrogen gas is not evolved when a metal reacts with nitric acid. It is because HNO3 is a strong oxidising agent. It oxidises the H2 produced to water and itself gets reduced to any of the nitrogen oxides (N2O, NO, NO2). But magnesium (Mg) and manganese (Mn) react with very dilute HNO3 to evolve H2 gas.