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].

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Why is the common magnesium ion Mg(II) and not Mg(I) when the second ionization energy is higher than the first ionization energy?

The first ionization energy for magnesium is given as $\pu{737.7 kJ/mol}$, and the second ionization energy is $\pu{1450.7 kJ/mol}$. Given this information, doesn't it take $\pu{737.7 kJ/mol}$ to ...
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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 ...
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How do atomic radius and nuclear charge influence ionisation energies?

This is actually a multiple choice question. Why is the first ionisation energy of neon higher than that of fluorine? A: Fluorine is more electronegative than neon B: Neon has a ...
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Why is the first ionisation energy of a sodium cation bigger than that of a neon atom?

I understand that the 1st ionization energy gets bigger for elements along a period from left to right and along a group from down to up. But why is the 1st ionization energy of $\ce{Na+}$ bigger ...
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Does electron shielding increase or stay constant moving LEFT to RIGHT across a period?

Does electron shielding increase or stay constant moving left to right across a period? I have read about both, and I just want to know which one is right. I believe that electron shielding remains ...
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Why do cations have higher ionization energies than neutral atoms?

I know that metals have low ionization energies and non-metals have high ionization energies, but once a metal/non-metal becomes a cation, why does the cation itself have a ionization energy higher ...
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Energy comparison between an atom and its ion

Is it possible to compare energy(enthalpy or similar) between an atom and its ion, possibly in the same state(gas)? For example, $\ce{O}$ and $\ce{O^+}$(intentionally cation), $\ce{Na}$ and $\ce{Na^+}...
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If fluorine has a lower electron affinity than chlorine, why does it have a higher ionization energy?

I have read that fluorine has a lower electron affinity than chlorine despite its lower atomic radius because its electron cloud is extremely dense. If this is the case, shouldn't the ionization ...
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Why does the ionization energy decrease anytime the atom size increases?

I would like to have a better understanding of the relationship that exists between the Ionization Energy commonly known as IE and the size of an atom. I think that the Ionization Energy can be ...
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Stability of unsaturated syn/anti 3-ladderane

In an oral exam for physical organic chemistry, one student was asked to explain the differences in the ionization potential ($IP$) of syn and anti tricyclo[$4.2.0.0^{2,5}$]octa-3,7-diene (unsaturated ...
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Successive ionization energies (work functions?) for metals

Are there tables for successive ionization energies for metals (like for gases)? All I can find are work functions to remove one electron from the surface of a metal into vacuum (and to keep it there)....
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Why is the photon energy of lithium flame coloring lower than that of cesium?

Why does $\ce{Li}$ give a red flame color which has lower photon energy compared to $\ce{Cs}$ which gives a violet flame color according to $E=h\nu$? This is my attempt: Since lithium has smaller ...
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How does H's ionization energy relate to its transition energy (Bohr's Model)?

I am currently reviewing some material about orbital energy levels. In my review book there is a short snipet that reads: The IE of $\ce{H}$ from its ground state ($n=1$) is $1312\ \mathrm{kJ/mol}$....
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Order of ionization enthalpy

The order of successive ionization enthalpies of group 15 are as follows : $$\Delta H_1<\Delta H_2<\Delta H_3$$ But as all the fifteen group elements have a very stable electronic ...
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Why is the first ionization enthalpy of zinc higher than expected?

The following sentence is stated in my current chemistry book: The first ionization enthalpy of zinc is higher because it represents an ionization from the $\rm 4s$ level. Now zinc does have an ...
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Why lithium gives flame coloration?

Theoretically speaking, beryllium and magnesium does not give flame test because their atoms are comparatively smaller and the valance electrons are strongly attached to the nucleus. Therefore their ...
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Relationship between ionization energy and orbitals [duplicate]

My chemistry book says that the ionization energy depends on the orbital an electron is taken from? I'm not sure I understand what it means. Could someone please explain this?
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“Exactly Equal” and “At Least” in electron excitation

When we examine IR spectra, we see troughs corresponding to absorption at exactly a specific frequency that corresponds to the energy needed to stretch certain bonds (although translational motions ...
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Ionization Energy and Electron Affinity

This is from my textbook. But in other reference books I am using and Wikipedia, there is not any mention of absolute zero while defining Ionization Energy and Electron Affinity. What does it mean? ...
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Why do the first and second ionizations of a diprotic acid produce the same hydronium ion concentrations in solution?

I was going through Oxtoby Chemistry when I got confused by the following passage in the textbook. It said that "two simultaneous equilibria are involved in the ionization of a diprotic acid such as ...
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Can the first ionization energy for a specific element be calculated?

I'm taking a first-year Inorganic Chemistry course in college, and stumbled upon this problem: For $\ce{Mn}$ and $\ce{P}$, calculate the first ionization energy and explain the difference between ...
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Why does ionization increase from Li to Be? [duplicate]

If ionization energy decreases from $\ce{N}$ to $\ce{O}$ due to the pairing of electrons (causing electric repulsion and greater potential energy) in the $\mathrm{2p}$ orbital in the $\ce{O}$ atom, ...
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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 ...
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Ionization energy comparison between K+ and Cl-

So I have encountered a question which looks very suspicious to me. If you have $\ce{Cl-}$ and $\ce{K+}$, Can you say that $\ce{K+}$ has more ionization energy than $\ce{Cl-}$? We know for a fact ...
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How to tell which compound has the biggest ionization energy?

I am preparing for my final exam, and I am very confused about ionization energy. An example question would be: Between the species $\ce{Ne, Na+, Mg^2+, Ar, K+, $\&$~Ca^2+}$, which one has the ...
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Why is ionisation energy of bismuth lower than lead?

Why is ionisation enthalpy of Bismuth less than that of Lead for it just comes after the latter in periodic table? First ionisation energy of bismuth is 703 kg/mol while that of lead is 715 kg/mol. I ...
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Relation between ionisation enthalpy and nature of bonds in boron

My notes given by institute states that: Due to small size of boron, the sum of its first three ionization enthalpies is very high. This prevents it to form $+3$ ions and forces it to form only ...
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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 ...
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Why don't halogens form cations like H+?

The first ionization energy of hydrogen is $1312\;\mathrm{kJ\cdot mol}^{-1}$, which is larger than that of halogens such as chlorine, bromine, and iodine. Given that observation, why don't halogens ...
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Why does F have a higher ionization energy than O?

The book I'm working from says F has a higher ionization energy than O because the nucleus has more protons so there is a higher attraction on the electrons. Isn't that balanced out by the higher ...
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Ionization energy and Electron Affnity

Which of the following statements correctly interprets the relationship between ionization energy, atomic radius Electron affinity when comparing two atoms. The correct choice as per my instructor ...
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Why is Ionization Energy definition restricted to gaseous atoms?

Here's the definition of ionization energy that I am learning at this level: energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of uni positively charged ...
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How much energy is required to make an ion?

So say that I have a normal hydrogen atom (not an isotope, just regular normal hydrogen atom) and I want to make it into an ion $\text{H}^+$. Since to make an ion of that formula I need to take away ...
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Can you in reality give neon a charge of +8?

First off, I am currently confused about why neon can even be ionized at all. But since it can be ionized, this is the energy required to give a mole of neon a charge of +8: ...
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Does ionization energy have anything to do with how reactive an element is?

According to my textbook, fluorine has a pretty high (compared to elements like sodium) first ionization energy. But why does it have such a high requirement to ionize? After all, it actively seeks ...
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Determine stable oxidation state from Ionization energy

Question: Given the first, second and third ionization energies of an element (7 eV, 12.5 eV and 42.5 eV respectively), how would one find the most stable oxidation state (or charge on the resultant ...
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Does caesium or francium have a lower ionization energy?

$\ce{Cs}$ and $\ce{Fr}$ are in the same group of lowest first ionization energy, but which element has the lowest ionization energy, and why?
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Anomalous trends in ionization energy

I want to address two exceptions in the trend of ionization energy across the period, that are causing me problems: Taking the second period as an example : The two exceptions from the general trend ...
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Why is electron gain generally exothermic?

I understand that we need to supply energy to counter the nuclear attraction when we remove electrons, and that is the reason why ionization energy is endothermic. However, why does an atom release ...
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is it possible to break the bonds of diatomic elements such as fluorine or iodine and create positive and negative ions by electron bombardment?

If I had a container in vacuum filled with $\ce{I2}$ gas and then I bombarded it with high speed electrons using an electron gun, would be able to get both $\ce{I+}$ and $\ce{I-}$ ions or would I ...
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How to find the formula of an binary oxide based on the ionisation energies? [closed]

I am a little confused about this multiple choice question and what the requirements are to answer it. It is for a year 11 chemistry student that I am helping and I think I am going in a little too ...
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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 ...
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Second ionization potential of Gadolinium

I notice that Gd has a second ionization potential which is significantly higher than would be expected from the general trend in the lanthanides (see this paper p. 945 for a graph). What is the ...
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How adding one more electron increases the ionization energy?

Elements of group 6A, compared to 5A, require less ionization energy due to the paired electrons of 6A. But a question arises: why does group 7A, compared to group 6A, require more ionization energy ...
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Signs of Exchange and Correlation Potentials

The exchange and correlation potentials refer to those defined in density functional theory. (See also http://en.wikipedia.org/wiki/Local-density_approximation) Define the exchange potential as $V_{x}...
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Why does the definition of ionisation energy only include gaseous atoms? [duplicate]

I know that in physics there is thermionic emission and the photoelectric effect. These are both method of removing electrons. I think these affects are only for metals due to their de-localized ...
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Determine most electronegative element based on successive ionization energy data

X, Y and Z are three unknown elements whose first 5 ionization energies are given below. Which of the 3 is the most electronegative?$$ \begin{array}{|c|c|c|c|c|c|}\hline &\text{IE}_1&\text{IE}...
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Which of the following atoms has the largest first ionization energy?

Of the following atoms, which has the largest first ionization energy? $\ce{Br}$ $\ce{O}$ $\ce{C}$ $\ce{P}$ $\ce{I}$ I got confused between $\ce{O}$ and $\ce{Br}$. The answer ...
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DFT Calculations, Atomic Ionization Potentials — Which Exchange-Correlation Functional to Use, to Preserve Koopmans Theorem?

I have a program which can perform density-functional calculations for atoms, given a density functional. Of course the simplest form of exchange potential to use is one relevant for a uniform ...
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Periodic trends: why is effect of protons greater than electrons?

Why is it that adding protons has a greater effect than electron-electron repulsion on periodic trends like atomic radius and ionization energy (assuming # of shells constant)? It seems that if ...