DeltaH formation = deltaH of broken bonds - deltaH of formed bonds
Broken bonds: tiple bond N-N and H-H bond
Formed bonds: N-H and N-N bonds
You also have to take note of the molar coefficients
deltaH formation = <span> [(N≡N) + 2 * (H-H)] - [4 * (N-H) + (N-N)]
= (945 + 2*436) - (4*390 + 240)
= 17 kJ/mol
The answer is 17 kJ/mol.</span>
Answer:
5. Selenium, because it does not have a stable, half-filled p subshell and adding an electron does not decrease its stability.
Explanation:
Electron affinity is the amount of energy released when an isolated gaseous atom accepts electron to form the corresponding anion.
Selenium:-
The electronic configuration of the element is:-
![[Ar]3d^{10}4s^24p^4](https://tex.z-dn.net/?f=%5BAr%5D3d%5E%7B10%7D4s%5E24p%5E4)
Arsenic:-
The electronic configuration of the element is:-
![[Ar]3d^{10}4s^24p^3](https://tex.z-dn.net/?f=%5BAr%5D3d%5E%7B10%7D4s%5E24p%5E3)
The 4p orbital in case of arsenic is half filled which makes the element having more stability as compared to selenium.
Thus, selenium has higher electron affinity because adding electron does not decrease the stability as in case of arsenic.
pure substances can be divided into two groups; elements and compounds
Phosphorous has 5 valence electrons and so gaining 3 electrons will make it isoelectronic with the stable noble gas argon, and will produce the P3- ion