Na , Mg , and Al are the elements having one two and three valence electrons resp. .Which of these elements is least reactive ? why ?

Open in App

Solution

We do not have a general trend in reactivity along the period. Elements try to gain noble gas configuration by gaining or losing electrons and hence they are reactive. Its depends on the ionization energy.
Along the period there is variation in the ionization energy which is irregular. For the half filled electronic configuration like nitrogen ionization energy is more as compared to the oxygen which is present in the next group of the periodic table. Thus it is difficult to remove the electrons from the nitrogen as compared to the oxygen. Likewise Mg has full filled electronic configuration and therefore it is difficult to remove the electron because of high ionization energy. Hence Mg will be least reactive.

Suggest Corrections

Similar questions

Q. Na, Mg and Al are the elements having one, two and three valence electrons respectively. Which of these elements (i) has the largest atomic radius, (ii) is least reactive? Justify your answer stating reason for each.

Q. Na, Mg and Al are the elements of the 3rd period of the Modern Periodic Table having group number 1, 2 and 13 respectively. Which one of these elements has the (a) highest valency, (b) largest atomic radius, and (c) maximum chemical reactivity ? justify your answer stating the reason for each.

Q. The first ionisation energies of six

3^{r d}

period elements are 496, 578, 738, 789, 1000 and 1012

{kJ mol}^{- 1}

. The elements to which these energies correspond respectively are:

F, Cl and Br are the elements each having seven valence electrons. Which of these (i) has the largest atomic radius, (ii) is most reactive? Justify your answer stating reason for each.

Q. Which one of the following elements exhibits the maximum number of valence electrons?
(Atomic numbers:

N a - 11, A l - 13, S i - 14, P - 15

)

Join BYJU'S Learning Program