Question

the following set is correct :-
(1) Li>K>B
(2) B > Li​

Answer 1

4th option cuz 2p6 is fully filled orbital

Answer 2

Explanation:

Successive ionisation energy of an element X are given below (in K. Cal)

IP1⠀⠀⠀⠀IP2⠀⠀⠀⠀⠀IP3⠀⠀⠀⠀⠀⠀IP4

165⠀⠀⠀195⠀⠀⠀⠀⠀556⠀⠀⠀⠀⠀595

Electronic configuration of the element X is :-

(1) 1s² , 2s² 2p^6 , 3s² 3p^6

(2) 1s², 2s¹

(3) 1s², 2s² 2p²

(4) 1s², 2s² 2p^6 , 3s² ✔

Explaination :-

As we see here, There is a sudden high jump between IP2 and IP3.

And we know that,

• Number of valence electrons = Number of lower value of IP before first highest jump.

So, Now, we can say that

Number of valence electrons = 2

because there's a high jump between IP2 and IP3 and Number of valence electrons = Number of lower value of IP before first highest jump.

Valence electrons is 2.

It means,

The element is of 2nd group (Alkaline earth metal).

And General electronic configuration of Group 2 is ns².

Hence,

Option 4 is correct because it's the element of Group 2, because it's valence shell configuration is 3s².