The content that complies with is the problem of basic occupychristmas.orgistry lecture 26. In this lecture we continue the conversation of Quantum Numbers and their usage in Electron Configurations as well as the connection of electron construction to the regular properties the the elements.

You are watching: Write the condensed electron configurations for the lu atom.

Electron Configuration

Electron configurations space the an overview of wherein the electrons are roughly a nucleus. Together we learned earlier, every neutral atom has actually a variety of electrons equal to its number of protons. What we will certainly do now is location those electrons right into an arrangement around the nucleus that suggests their energy and also the form of the orbit in i beg your pardon they space located. Right here is a review of the species of orbitals and how numerous electrons each deserve to contain:


So based upon what us know about the quantum numbers and using the graph above, you require 2 electrons to to fill an s orbital, 6 electron to to fill a p orbital, 10 electron to fill a d orbital and 14 electrons to fill the f orbital. However what us haven\"t disputed is just how these orbitals obtain filled...the bespeak of fill.

Order of Fill

The order in which electrons are inserted into the orbitals is based upon the bespeak of their energy. This is described as the Aufbau principle. The lowest energy orbitals to fill first. As with the quantum number themselves this stimulate was determined by calculation and is summarized by the following chart:


or you have the right to just usage the routine table:


How to write an Electron Configuration

The symbols provided for composing the electron configuration start with the covering number (n) complied with by the form of orbital and also finally the superscript indicates how many electrons room in the orbital.


For example:

Looking at the periodic table, you can see that Oxygen has actually 8 electrons. Based on the order of to fill above, this 8 electrons would certainly fill in the complying with order 1s, 2s and also then 2p. For this reason Oxygen\"s electron configuration would be O 1s22s22p4.

Special Cases

Configurations of ions current a special situation of electron construction and likewise demonstrate the factor for the development of those ions in the very first place.

If you have to write the full electron configuration for an anion, climate you are just adding additional electrons and the construction is just continued.

For example, we recognize that Oxygen constantly forms 2- ions as soon as it provides an ion. This would include 2 electrons to its common configuration making the new configuration: O2- 1s22s22p6. V 10 electron you should note that oxygen\"s electron construction is now exactly the very same as Neon\"s. We talked around the truth that ions form because they can become an ext stable through the gain or loss of electron to become like the noble gases and now you have the right to actually see how they end up being the same.

The electron configurations for Cations are also made based on the number of electrons yet there is a slight difference in the method they room configured. Very first you should write their regular electron configuration and then when you remove electrons you need to take them indigenous the outermost shell. Keep in mind that this is not always the same way they to be added.

Here is an instance of what ns mean:

Iron has 26 electron so its normal electron configuration would be: Fe 1s22s22p63s23p64s23d6

When us make a 3+ ion for Iron, we must take the electrons from the outermost shell an initial so that would be the 4s covering NOT the 3d shell: Fe3+ 1s22s22p63s23p63d5

One other keep in mind on creating electron configurations: A short cut. As soon as writing few of the lower table configurations the complete configuration deserve to be reasonably long. In this cases, you have the right to use the ahead noble gas to abbreviation the construction as presented below. Girlfriend just have actually to end up the construction from where the noble gas pipeline it:



As v every various other topic we have actually covered to day there space exceptions come the bespeak of fill as well. But based on the electron configuration that room generated, these exceptions are straightforward to understand.

In the d block, particularly the groups containing Chromium and Copper, there is an exception in how they room filled.

Here space the actual configurations:


In these columns, the 4s and 3d

Practice, Practice, Practice

There are numerous quizzes ~ above electron configuration you have the right to practice with located here

Orbital Diagrams

Another way to stand for the stimulate of to fill for an atom is by utilizing an orbital diagram often referred to together \"the tiny boxes\":


The box are provided to represent the orbitals and to present the electrons inserted in them. The order of fill is the same yet as you deserve to see from above the electron are put singly into the boxes prior to filling them v both electrons. This is called Hund\"s Rule: \"Half fill prior to you full fill\" and again this ascendancy was established based on energy calculations that shown that this to be the method atoms actually spread their electrons into the orbitals.

Periodic Properties

One of the really cool things around electron configurations is their connection to the periodic table. Usually the periodic table was created so that elements with comparable electron configurations would certainly be aligned into the same groups (columns).


Periodic Table reflecting last orbital filled because that each element

The regular table shown above demonstrates just how the configuration of each facet was set so the the critical orbital filled is the same other than for the shell. The reason this was done is that the construction of an facet gives the facet its properties and similar configurations yield comparable properties.

Let\"s walk through few of the periodic Properties that are influenced straight by the electron configuration:

Atomic Size

The size of atoms boosts going down in the regular table. This need to be intuitive because with each row of the table friend are adding a shell (n).

What is no as intuitive is why the size decreases from left come right. But again the building of the electron configuration offers us the answer. What are you doing as you go across the periodic table? Answer, including protons to the cell core and adding electrons come the valence covering of the element. What is not transforming as you cross a period? Answer, the inner shell electrons.

So think of the this way, the inner covering electrons space a shield against the traction of the nucleus. As you overcome a period and increase the number of protons in the nucleus you increase its pull but due to the fact that you space only including electrons to the brand-new shell the shield is no increasing however remains the exact same all the way across. This way the traction on the electrons being added to the valence shell is increasing steadily every the method across. What happens if you pull harder top top the electrons? Well, they come closer to the nucleus and also the size of the atom decreases. The result of the cell core pulling ~ above the electrons being added throughout a duration is called the reliable nuclear charge and also is calculated together ZEff = #protons - main point # Electrons.

So for instance the pull felt through Sulfur would certainly be ZEff = 16 - 10 = +6



Electronegativity may be the most vital of the regular properties you have the right to learn and understand because so many other nature are rely on that is value. Electronegativity is an atoms ability to traction electrons in the direction of itself.

Electronegativity is usually expressed through the Pauling Scale and also the values were determined experimentally. The table listed below shows the range values for the elements.


The electronegativity values boost from left come right and also bottom to optimal in the periodic table excluding the Noble gases. The many electronegative aspect is Fluorine.

From this electronegativity values we have the right to derive the fads of two other periodic properties: Ionization Energy and also Electron Affinity.


Ionization Energy

Ionization energy is the quantity of energy required to remove an electron indigenous an atom. Every ionization energies are hopeful values because all of these removals (even those for aspects that kind positive ions) require input that energy. The an ext electronegative the element, the greater the ionization eneregy.

See more: Question : Which Of The Following Is Not A Connective Tissue ?

Electron Affinity

The Electron Affinity that an facet is the lot of energy gained or released v the addition of one electron. The electronegativity and Electron Affinity boosts in the exact same pattern in the regular table. Left to right and bottom to top.