Ionization Energy: Across Period or Metal to Non-Metal?

[khurram usman]

ionization energy...?

i got a mcq in my test:

Ionization energy increases:
a) across a period
b) down a group
c) from metal to non-metal
d) all of above

i am confused between option 'a' and 'c'
what should be the right answer?

 

[dacruick]

well if ionization energy is the energy required to remove and electron, then what do you think?

in other words, what exactly are you confused about?

 

[khurram usman]

well if ionization energy is the energy required to remove and electron, then what do you think?

in other words, what exactly are you confused about?

well as we move from left to right across a period then more energy is required to remove electron: option A
and similarly as we go on from metals to non metals then also ionization energy increases as non metals lose electron with difficulty: option C

above two options seem similar ...what should i do?

 

[dacruick]

Hmm I see. Well does the ionization energy increase from every metal to every non metal? I admit that I'm not positive about this(were takling about electrons), but it seems likely that some metals hang onto electrons more than some non-metals.

EDIT: Ahh I found something. Hydrogen is a metal, and it has a higher ionization energy than a handful of non metals. So go with A

EDIT #2: I've also found that Oxygen has a lower ionization than its neighbour to the left, Nitrogen. So it seems that there are exceptions to both A) and C), but they both seem to be right in terms of trends. My final verdict is that the question could be better