Question

The first (ΔiH1) and the second (ΔiH) ionization enthalpies (in kJ mol–1) of a few elements are given below:

Elements ΔiH1 ΔiH2
I 2372 5251
II 520 7300
III 900 1760
IV 1680 3380


Which of the above elements is likely to be :


(a) the most reactive metal.

(b) the most reactive non-metal.

(d) Noble gas.

Answer 1

Noble gases are the least reactive, that is, they do not like any change in their electronic configuration - so their first ionisation enthalpy would be remarkably higher than the rest.

Answer 2

I -d

Answer 3

is it 520 7300

Answer 4

but reactive metals also have 1 or 2 valance eletron

Answer 5

so it need lees ionization energy

Answer 6

so it can be reactive metal tooo

Answer 7

ionization enthalpies - it is the min amt of energy req to remove the electron

Answer 8

so hw it can be used to gain electron

Answer 9

OH NO! GODDAMN ME!!!! O.O

I have been thinking along the lines of electron gain enthalpy all along.. Damn me!
I am so so RUSTY!!!!!!

I am sorry for the mix up, I am posting a revised solution in a jiffy..

Answer 10

ok...

Answer 11

Okay so, again for the noble gas, a huge amount of energy would be required to remove an electron from its stable electronic configuration. (Much greater than in comparison with a metal or a non metal)

Answer 12

As for a metal, the most-reactive metal would be one with the minimum possible no. of electrons in its valence shell, so losing an electron would be favorable. Hence the first ionisation energy would be pretty lo comparatively. But now as the atom attains a stable state after losing one electron, losing a second electron would be extremely unfavorable for its configuration, and so the second IE would be exceptionally high for compared to the first IP.

Answer 13

so noble gas = element 1

Answer 14

Yes, that's correct.

Answer 15

the most reactive metal = ?

Answer 16

Think.. I've provided all the explanations and hints..

Answer 17

sorry i have nt seen that let me read

Answer 18

the most reactive metal = element 2

Answer 19

@apoorvk

Answer 20

Yeah, that's right as well!

Answer 21

then the most reactive non-metal.

Answer 22

okay this one hmm - a non-metal has a incomplete octet requiring 1,2, or 3 more electrons. A very reactive one would be an atom that needs just one more electron and would be 'aching' for it - so now, removing an electron would be detrimental to its 'dreams' of achieving the octet :P
So, if you think, it's first IP would be pretty high (though not as high as that for the noble gas), and ofcourse, the consecutive IPs would be pretty high as well!

So, any ideas? ;)

Answer 23

is it element 4

Answer 24

Aye aye! correct-o!

So you think you've understood the fundae behind this?

Answer 25

yup thxxxx !! hey can u prove cos(x+y) = cosx.coy - sinx . siny

Answer 26

Hmm, post it in the maths section please, I'll try!

Answer 27

ok