The increasing order of first ionization enthalpies of the elements B,

1.	The increasing order of first ionization enthalpies of the elements B, P, S and F (lowest first) is .........
Answer» `P lt S lt B lt F` `F lt S lt P lt B` `B lt S lt P lt F` `B lt P lt S lt F` SOLUTION :"Generally in a period as atomic number is higher its first IONISATION enthalpy is greater", ACCORDINGLY first ionisation enthalpy of `B lt F` (both of second period) and of `P lt S` (both of third period) The `I^(ST)` ionisation enthalpy decreases from top to botton in a GROUP . ` :. I^(st)`ionisation potential order should be: `B lt F " and " P lt S` `P [Ne] 3s^(2) 3px^(1) 3py^(1) 3p_(2)^(1)` and `S [Ne] 3s^(2) 3px^(2) 3py^(1) 3p_(z)^(1)` P has stable half filled (p) Electronic configuration, hence`Delta_(i)H(P) gt Delta_(i)H(S)` ` :. ` The correct order is `B lt F " and " S lt P ` F is of smallest size among these all. `:. F`has highest `Delta_(i)H` ` :. `Orderis `B lt S lt P lt F`

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