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Questions tagged [ionization-energy]

The ionization energy of an atom or molecule describes the minimum amount of energy required to remove an electron from the atom or molecule in the gaseous state. Do not confuse with [electron-affinity].

The ionization energy or ionization potential is the energy necessary to remove an electron from the neutral atom. It is a minimum for the alkali metals which have a single electron outside a closed shell. It generally increases across a row on the periodic maximum for the noble gases which have closed shells. For example, sodium requires only $\pu{496 kJ/mol}$ or $\pu{5.14 eV/atom}$ to ionize it while neon, the noble gas immediately preceding it in the periodic table, requires $\pu{2081 kJ/mol}$ or $\pu{21.56 eV/atom}$. The ionization energy is one of the primary energy considerations used in quantifying chemical bonds.

See also:

  1. Wikipedia
  2. Hyperphysics
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Ionization energy of beryllium

Suppose I have $\ce{Be^3+}$. What would be its 4th ionization energy? By trying to solve the issue I saw that its a "hydrogen-like" atom – means that beryllium left with only $1$ electron in his valance shell. Hence, I can use the Bohr atom model to…
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In an emission spectrum, the limit of convergence at higher frequency corresponds to the first ionization energy

This is one of the syllabus points in the IB syllabus 12.1. We are advised to use the formula for the energy to remove one electron: $$E = hν$$ which apparently is the same as $$E_2 - E_1$$ where $E_2$ is the energy of the convergence limit and…
Manolis Gustavsson
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How are 2nd, 3rd, etc. ionization energies measured?

I am learning about ionization energies and I understand roughly how the first ionization energy can be measured. But how are the subsequent energies measured? For the 1st ionization energy the neutral atoms are excited by photons or electrons of…
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Why is the 2nd ionization energy of chloride similar to that of sulfur?

The first ionization energy of chloride is significantly greater than that of sulfur. I suggest that this is very expected as the effective nuclear charge of chloride is higher and additionally, sulfur has even more electron-electron repulsion due…
the24
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Why can the electron gain process be endothermic or exothermic whereas the ionistation process is always endothermic?

I know that this may seem a very silly question to some of you but please help me.I am extremely confused. PS:Sorry if you accidentally stumbled to this question.I can't find the appropriate tags
user52631
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Reason for the differences in third ionisation energy between elements (magnesium and fluorine)

The question is "Why is the third ionisation energy of magnesium higher than that of fluorine?" Although I understand that differences in ionisation energy have several factors governing it, e.g. the shielding effect, distance from the nucleus,…
CCC
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Why does fluorine atom have a higher ionization energy than oxygen atom?

The book I'm working from says $\ce{F}$ has a higher ionization energy than $\ce{O}$ because the nucleus has more protons so there is a higher attraction on the electrons. Isn't that balanced out by the higher number of electrons or is it because…
Keith Whittingham
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Compare the ionization energies of C and Cl?

I saw a test question today that basically boiled down to comparing the ionization energies of $\ce{C}$ and $\ce{Cl}$. I know that in the periodic table, ionization energy generally increases as we move right across a row (because nuclear charge…
math_lover
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Second Ionisation Energy Confusion

It is intuitive that the second ionisation will require more energy than the first. However, I'm having trouble explaining exactly why. I came across this other question on a similar topic: Why second ionisation energy greater than the first? The…
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Rate the following ions in increasing ionization energy

Sr2+, Rb1+, S2-, P3- I believe it is P3- < S2- < Rb1+ < Sr2+ because it should be easier to take an electron away from the negatively charged ions, but I'm not sure about the Rb and Sr because they both have their electrons taken out of their outer…
sr123
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Comparing first, second, and third ionization energies between atoms

Among the elements boron, carbon, nitrogen, and magnesium, what are the first ionization energies from least to greatest? What about the second and third ionization energies? I understand the first ionization energy is given by the following…
Cyclopropane
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Be and B ionization energies

Why does Be have a higher ionization energy than B? I know that it has a filled 2s orbital, but what's the more accurate explanation?
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Why is ionization always an endothermic process?

My textbook says removing an electron always requires an input of heat. That makes sense because of coulombic force between electron and nucleus. But it also says that the process is endothermic always. Why is that? In the case of Na, after the…
Nova
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is Li ion less stable than Li atom?

so our teacher introduced the concept of ionization energy... heres my doubt : if we remove an electron from , say, Lithium , we need to supply energy first and that will be very less compared to the energy we'll have to supply to , say, oxygen.…
Fatimah Rashid
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Ionisation Energy and Evidence of Subshells

In Chemistry Electron classes, I was told that first ionisation energy gives evidence of electron shells. Now is this true due to the steep increase shown on a first ionisation graph when the previous shell is emptied, or am I wrong…
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