Question

Ionization energy Ionization Energy is the energy required to remove an electron from an atom or ion in the gaseous state. The ionization energy is always positive because it takes energy to remove and electron. 1) Using the figure on the left, which elements have the highest first ionization energies? 2) Does this make sense as to why they have high Ionization energy? ell tentation energi 3) Which elements have the lowest first ionization energies? 4 Does this make sense as to why they have high Ionization energy? Periodic Table 5. What is the general trend in first ionization energies as you go across a period (row)? 6) Explain why this general trend is observed.

Answer 1

1) Zero group elements or noble gases (He, Ne, Ar, Kr and Xe) have the highest first ionization energies.

In the given graph noble gases are present on the top which indicates the higher Y-axis value which is the first ionization energy in kJ/mol and hence from the graph it is known that noble gases have the highest first ionization energies.

2) Yes. The graph make sense for why noble gases have the highest first ionization energies.

Noble gases are the elements having completed valency shell electronic configuration which is the most stable. (hence they are on top indicating the filling up of that shell completes in that period and from the next atom valency electrons enter into next higher shell).

3) Alkali metals have the lowest first ionization energies.

In the graph given alkali metals are the elements which present at the bottom of the table indicating a lower Y-axis value and hence they have the lowest first ionization energies.

4) No. Actually alkali metals have the lowest ionization energies

There is only one valency electron in these metals as are started with a new shell in each group (Li in 2nd group, Na in 3rd group, K in 4th group etc). They readily loss their valency electron to attain fullfilled noble gas configuration and hence they have low ionization energies.