# Chem 1 ionisation question

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#1
The table below gives the successive ionization energies of an element. Deduce the group in the periodic table that contains this element.
…………………………(1st) (2nd) (3rd) (4th) (5th)
Ionisation energy: 590 1150 4940 6480 8120

0
7 years ago
#2
Look at the differences:

590 1150 4940 6480 8120
......560...3790.1540.1640

The numbers should increase as the p+:e- ratio increases, but 3790 is a big jump, i.e. MUCH more energy than might be expected is needed. This is caused by the e- is being removed from a new shell.

Put another way, the first e- is fairly easy to remove, the second one is about twice as hard, the third one is much harder, the fourth is a bit harder etc.

BTW, it is Ca.
0
7 years ago
#3
Group 3 because that is the largest increase in ionization energy.
0
7 years ago
#4
(Original post by jazzie14)
The table below gives the successive ionization energies of an element. Deduce the group in the periodic table that contains this element.
…………………………(1st) (2nd) (3rd) (4th) (5th)
Ionisation energy: 590 1150 4940 6480 8120

How you would approach this question is to look at the jumps in energy between each stage. So for instance here we start with 590, then roughly double that to remove the second electron. Then a big jump up to 4940. So what that tells us is that the element REALLY doesn't want to give up a 3rd electron. You have to look at the periodic table to find something that gives up 2 electrons without too much trouble, but really doesn't want to enter a 3+ state.
1
7 years ago
#5
(Original post by i'mlaura)
Group 3 because that is the largest increase in ionization energy.
Group 2, no?
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7 years ago
#6
(Original post by SamTheMan95)
Group 2, no?
That isn't as big an increase as the third ionization energy though.
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#7
it does make sense what you are all saying but they are asking what group, not what element? so surely there's an easier way then looking at all the elements? answer is indeed group 2
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7 years ago
#8
(Original post by i'mlaura)
That isn't as big an increase as the third ionization energy though.
1 ionisation is low
2 is not that much bigger
3 is a massive increase

So the third electron requires a lot of energy to remove, so it must be removed from from another shell. So the element had two electrons in its outer shell ie. Group 2
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7 years ago
#9
Group 2 due to two electrons being in the outer shell indicated by the large jump in ionisation energies between the 2nd and 3rd ionisation energies
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7 years ago
#10
(Original post by jazzie14)
it does make sense what you are all saying but they are asking what group, not what element? so surely there's an easier way then looking at all the elements? answer is indeed group 2
"You have to look at the periodic table to find something that gives up 2 electrons without too much trouble, but really doesn't want to enter a 3+ state."

Yes, what I said there applies to all of group 2. It would be difficult to pin down exactly which element it is just from that data.
0
7 years ago
#11
(Original post by SamTheMan95)
1 ionisation is low
2 is not that much bigger
3 is a massive increase

So the third electron requires a lot of energy to remove, so it must be removed from from another shell. So the element had two electrons in its outer shell ie. Group 2
Thank you, I'm doing this exam as well and I thought I understood it.
0
7 years ago
#12
(Original post by i'mlaura)
Thank you, I'm doing this exam as well and I thought I understood it.
Good luck. If you ever need help, the chemistry section always has the answer
1
9 months ago
#13
State the group in periodic table an elemen belongs
0
9 months ago
#14
The first four ionization energies of an elemen ar :590,1150,4949and 6490
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