Difference Between Excitation and Ionization Potential

Main Difference – Excitation vs Ionization Potential

Excitation and ionization potential are two terms used in chemistry to explain the relationship between electrons and atomic nuclei of chemical elements. Atomic nuclei are composed of protons and neutrons. Hence, they are positively charged. There are electrons in movement around the nucleus along certain energy levels. Electrons are negatively charged. Excitation is the movement of an electron from a lower energy level to a higher energy level by absorbing energy. It makes an atom move from a ground state to an excited state. Ionization energy is the removal of an electron from a neutral gaseous atom. This makes a cation; when an electron is removed, the atom does not have a negative charge to neutralize the positive charge of the atom. The main difference between excitation and ionization potential is that excitation explains the movement of an electron from a lower energy level to a higher energy level whereas ionization potential explains the complete removal of an electron from an energy level.

Key Areas Covered

1. What is Excitation
     – Definition, Explanation, Electromagnetic Spectrum
2. What is Ionization Potential
     – Definition, First Ionization Energy, Second Ionization Energy
3. What is the Difference Between Excitation and Ionization Potential
     – Comparison of Key Differences

Key Terms: Atomic Nuclei, Electromagnetic Spectrum, Electron, Excitation, Excited State, Ground State, Ionization Energy, Ionization Potential

Difference Between Excitation and Ionization Potential - Comparison Summary

What is Excitation

In chemistry, excitation is the addition of a discrete amount of energy to a system such as an atomic nucleus, an atom or a molecule. Excitation causes the change of the energy of the system from a ground energy state to an excited energy state.

The excited states of systems have discrete values rather than a distribution of energies. This is because excitation occurs only when an atom (or any other system mentioned above) absorbs a certain portion of energy. For example, in order to make an electron move to an excited state, the amount of energy that should be given is equal to the energy difference between the ground state and the excited state. If the given energy is not equal to this energy difference excitation does not occur.

Same as for electrons, protons and neutrons in atomic nuclei can be excited when they are given the required amount of energy. But the energy required to make the nucleus move to an excited state is very high when compared to that of electrons.

A system does not remain in the excited state for a long time since an excited state having a high energy is not stable. Therefore, the system needs to release this energy and come back to the ground state. The energy is released in the form of emission of quantum energy, as photons. It occurs usually in the form of visible light or gamma radiation. This return is called decay. Decay is the inverse of excitation.

Electromagnetic Spectrum

Difference Between Excitation and Ionization Potential

Figure 1: Electromagnetic Spectrum of Hydrogen

When an electron has absorbed energy and comes to an excited state, it returns to its ground state by emitting the same amount of energy. This emitted energy leads to the formation of an electromagnetic spectrum. The electromagnetic spectrum is a series of lines. Each line indicates the energy emitted when returning to the ground state.

What is Ionization Potential

Ionization potential or ionization energy is the amount of energy required to remove the most loosely bound electron from a neutral, gaseous atom. This electron is a valence electron because it is the electron that resides farthest from the atomic nucleus. The ionization of a neutral atom causes the formation of a cation.

The removal of this electron is an endothermic process, in which energy is absorbed from the outside. Therefore, the ionization potential is a positive value. In general, closer the electron to the atomic nucleus, higher the ionization potential.

For elements in the periodic table, there are ionization potentials given as first ionization energy, second ionization energy, third ionization energy and so on. First ionization energy is the amount of energy required to remove an electron from a neutral gaseous atom, forming a cation. Second ionization energy of that atom is the amount of energy required to remove an electron from the cation formed after first ionization.

Main Difference - Excitation vs Ionization Potential

Figure 2: First Ionization Energy Variations in Periodic Table

In general, ionization energy decreases down the group of the periodic table. This is due to the increase in atomic size. When the atomic size increases, the attraction to the farthest electron from atomic nucleus decreases. Then it is easy to remove that electron. Hence, a less energy is required, resulting in a decreased ionization potential.

But when going from left to right along a period of the periodic table, there is a pattern of ionization energy. The ionization energies vary based on the electronic configuration of elements. For example, the ionization energy of group 2 elements is higher than that of group 1 elements and group 3 elements as well.

Difference Between Excitation and Ionization Potential

Definition

Excitation: Excitation is the addition of a discrete amount of energy to a system such as an atomic nucleus, an atom or a molecule.

Ionization Potential: Ionization potential is the amount of energy required to remove the most loosely bound electron from a neutral, gaseous atom.

Purpose

Excitation: Excitation explains the movement of an electron from a lower energy level to a higher energy level.

Ionization Potential: Ionization potential explains the removal of an electron from an energy level completely.

Energy Change

Excitation: Excitation requires energy from outside, but this energy is soon released as photons.

Ionization Potential:  Ionization potential is the amount of energy absorbed by an atom, and it is not released again.

End Product Stability

Excitation:  Excitation forms an excited state which is unstable and has a short lifetime.

Ionization Potential: Ionization potential forms a cation which most of the times is stable after removal of an electron.

Conclusion

Excitation and ionization potential in chemistry are two terms used to explain the relationship between energy changes and atomic behavior of chemical elements. The main difference between excitation and ionization potential is that excitation explains the movement of an electron from a lower energy level to a higher energy level whereas ionization potential explains the complete removal of an electron from an energy level.

 Reference:

1.  “Excitation.” Encyclopædia Britannica, Encyclopædia Britannica, inc., 17 Aug. 2006, .
2. “Excited state.” Wikipedia, Wikimedia Foundation, 22 Jan. 2018, .
3. “Ionization Energies.” Ionization Energy, .

Image Courtesy:

1. “Hydrogen spectrum” By OrangeDog – Own work by uploader. A logarithmic plot of λ for, where n′ ranges from 1 to 6, n ranges from n′ + 1 to, and R is the w:Rydberg constant via
2. “First Ionization Energy” By Sponk (PNG file)Glrx (SVG file)Wylve (zh-Hans, zh-Hant)Palosirkka (fi)Michel Djerzinski (vi)TFerenczy (cz)Obsuser (sr-EC, sr-EL, hr, bs, sh)DePiep (elements 104–108)Bob Saint Clar (fr)Shizhao (zh-Hans)Wiki LIC (es)Agung karjono (id)Szaszicska (hu) – Own work based on: Erste Ionisierungsenergie PSE color coded.png  by Sponk via

About the Author: Madhusha

Madhusha is a BSc (Hons) graduate in the field of Biological Sciences and is currently pursuing for her Masters in Industrial and Environmental Chemistry. Her interest areas for writing and research include Biochemistry and Environmental Chemistry.

Leave a Reply


Related pages


what does induction mean in physicsconcrete noun examplesdifference between typical and atypical antipsychoticscomparison between osmosis and diffusioncad cvdwhat is the difference between herbs and spicesare limes bittermeaning of foregofeatures of android lollipop 5.1.1the chemical name of vitamin c isdifference between sugar beet and sugarcanefacetious meansinverting and noninvertingseed structure of monocot and dicotinferences vs observationssimilarities of operant and classical conditioningdifference between body lotion and moisturisermicrometer caliper readingcalculating cpi examplesmetaphor and simile differencewhat is the difference between base and alkalinewhat is a distinguishing characteristic of a saturated fatty acidwhat is the difference between yams & sweet potatoesdefinition myoglobinenunciation definitionwhat is progressive waveepinephrine and norepinephrine differencesstructure of neutrophilscentripetal force vs centrifugal forceembryo wikipedialysosomes structureomnivores and herbivoreszygote embryodifference between cannula and catheterdifference between syllabus and course outlinenaming and classification of enzymesunits of kinematic viscositydifference between drama and theatre studiesdifference in meiosis and mitosisprove nounforging castingligroin chemical structurepast participle drunkcharacteristic of surrealismwhat is pomelo fruitplay drama theaterdefine subordinating conjunctionumayyad abbasidexample concrete nounwhat is pinocytosisrolling friction is less than sliding frictionwhat does the new zealand flag meanwarm blooded animals aretypes of vacuoledefinition of kitchen tools and equipmentsdefinition of rotational motion in physicscommon collective nounsis bi carb the same as baking sodaelegy characteristicsagave vs honeybeets vs sugar beetsdeductive essaydifference between polymer and copolymerd fructose l fructosedifference between unicellular organisms and multicellular organismssynesthesia exampleacculturation assimilationsmooth endoplasmic reticulum locationwhat is cologne and perfume differencewhat are cytokines and chemokinesmalamute vs siberian huskyconvex lense diagramenculturalizationdistinguish between positive and normative economicsdifference between frog and toadthe difference between rationalism and empiricism is thatsardonic humor definitiondefinition aliphaticacne versus pimples