Question

Arrange the following in order of increasing radio?

(i) Mg²⁺, Mg, Mg⁺
(ii) N, O, P

Give quick and accurate answer.​

Answer 1

(i) Mg²+ < Mg* < Mg

- The ionic radius of the cation is the smaller than the parent atom due to relatively an more charge in the form of nucleus.

- Hence, Mg²+ has the smallest radius, Mg+ has more than Mg²+ and Mg has the largest radius.

_______________________________

(ii) O < N < P

- The covalent radius of O is 66 pm, of N is 70 pm and that of P is 110 pm.

_______________________________

Answer 2

Answer:

Question:-

• Mg²⁺, Mg, Mg⁺
• N,O,P

Concept:-

• The size of a positive ion is smaller than the size of the orignal element as it has lost its valence electrons.Example:Al3+ (ion) is smaller than Al (orignal element) as Aluminium ion has lost three electrons from the valence shell so it has 1 shell less than the orignal atom.
• The size of an atom decreases in a period from left to right and increases in a group from top to bottom.

Answer:-

• Mg²⁺<Mg⁺<Mg
• O<N<P

Reason for answer 1:-

• In each case we notice that the more the electropositivity lesser the number of electrons as if an atom is neutral so it's size will be largest so it's electronic configuration is 2,8,2 so it has the highest number of electrons than the other two,the second ion that is mono-positively charged is second smaller it has electronic configuration 2,8,1 and it also have 2 shells but 1 less electron and the third ion Mg2+ will be the smallest as it's electronic configuration is 2,8 so it has the least electron and has only 2 shells.

Reason for answer 2:-

• Nitrogen has atomic number 7 and oxygen atomic number 8,they belong to same period I.e period 2 and hence, and as we know the size of an atom decreases in a period as we move from left to right (exception noble gases are greater than halogens due to electron-electron affinity but are not as greater than the alkali metals of same period).Phosphorous(P) belong to period 3 of the modern periodic table and hence it has greater size than Nitrogen and Oxygen has there is 1 more shell added with it.

More information:-

• In periodic table all periodic properties like electronegativity,electron affinity,ionisation energy depends upon the atomic size/radius/volume of an atom.