The contents that complies with is the problem of basic allisonbrookephotography.comistry lecture 26. In this class we continue the discussion of Quantum Numbers and also their use in Electron Configurations and the connection of electron construction to the periodic properties that the elements.

You are watching: Write the full ground-state electron configuration for each element.

Electron Configuration

Electron configurations are the summary of whereby the electron are about a nucleus. Together we learned earlier, each neutral atom has a number of electrons same to its number of protons. What we will do now is location those electrons right into an arrangement approximately the cell core that shows their energy and also the shape of the orbit in which they room located. Here is a an overview of the types of orbitals and how countless electrons each can contain:


So based on what us know around the quantum numbers and also using the graph above, you need 2 electrons to fill an s orbital, 6 electrons to fill a ns orbital, 10 electron to to fill a d orbital and also 14 electron to to fill the f orbital. But what us haven"t questioned is just how these orbitals acquire filled...the order of fill.

Order of Fill

The order in which electrons are placed into the orbitals is based on the stimulate of your energy. This is described as the Aufbau principle. The lowest power orbitals to fill first. As with the quantum numbers themselves this order was established by calculation and also is summarized by the adhering to chart:


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


How to create an Electron Configuration

The symbols used for composing the electron configuration begin with the covering number (n) followed by the kind of orbital and finally the superscript indicates how many electrons space in the orbital.


For example:

Looking in ~ the periodic table, you have the right to see that Oxygen has actually 8 electrons. Based on the bespeak of to fill above, this 8 electrons would certainly fill in the following order 1s, 2s and then 2p. For this reason Oxygen"s electron configuration would certainly be O 1s22s22p4.

Special Cases

Configurations of ions existing a special situation of electron configuration and also demonstrate the factor for the formation of those ion in the an initial place.

If you should write the complete electron configuration for an anion, climate you room just adding additional electrons and the construction is simply continued.

For example, we recognize that Oxygen always forms 2- ions once it provides an ion. This would add 2 electrons to its normal configuration make the brand-new configuration: O2- 1s22s22p6. V 10 electrons you must note that oxygen"s electron configuration is now exactly the very same as Neon"s. Us talked about the truth that ions kind because they can become more stable through the get or ns of electron to end up being like the noble gases and also now you can actually see exactly how they come to be the same.

The electron configurations for Cations are additionally made based upon the variety of electrons but there is a slight difference in the way they room configured. Very first you have to write their common electron configuration and then when you eliminate electrons you need to take them from the outermost shell. Note that this is not always the same method they to be added.

Here is an instance of what i mean:

Iron has actually 26 electron so its typical electron configuration would certainly be: Fe 1s22s22p63s23p64s23d6

When we make a 3+ ion for Iron, we need to take the electron from the outermost shell very first so that would certainly be the 4s covering NOT the 3d shell: Fe3+ 1s22s22p63s23p63d5

One other note on creating electron configurations: A quick cut. Once writing several of the lower table configurations the full configuration deserve to be reasonably long. In these cases, you can use the previous noble gas to abbreviation the configuration as shown below. Girlfriend just have to finish the construction from whereby the noble gas leaves it:



As through every other topic we have actually covered to date there space exceptions come the order of fill as well. But based on the electron configurations that space generated, these exceptions are simple to understand.

In the d block, especially the groups containing Chromium and Copper, there is an exemption in just how they space filled.

Here room the actual configurations:


In these columns, the 4s and 3d

Practice, Practice, Practice

There are many quizzes on electron configuration you can practice with located here

Orbital Diagrams

Another means to stand for the bespeak of fill for one atom is by making use of an orbital diagram often referred to as "the tiny boxes":


The box are offered to stand for the orbitals and to present the electrons put in them. The order of fill is the same however as you have the right to see from above the electron are inserted singly into the boxes before filling them v both electrons. This is dubbed Hund"s Rule: "Half fill prior to you complete fill" and also again this dominion was established based upon energy calculations that indicated that this to be the means atoms actually dispersed their electrons into the orbitals.

Periodic Properties

One of the yes, really cool things around electron configurations is their connection to the routine table. Usually the regular table was constructed so that aspects with similar electron configurations would be aligned into the same teams (columns).


Periodic Table mirroring last orbital filled for each element

The routine table shown over demonstrates exactly how the configuration of each facet was set so that the critical orbital to fill is the same other than for the shell. The reason this was done is the the construction of an element gives the aspect its nature and comparable configurations yield comparable properties.

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

Atomic Size

The size of atoms boosts going under in the periodic table. This must be intuitive because with each row of the table you are adding a shell (n).

What is not as intuitive is why the size decreases indigenous left to right. Yet again the building and construction of the electron configuration gives us the answer. What are you doing together you go across the periodic table? Answer, adding protons come the cell core and including electrons to the valence shell of the element. What is not an altering as you overcome a period? Answer, the inner shell electrons.

So think of the this way, the inner shell electrons are a shield versus the pull of the nucleus. As you overcome a period and rise the variety of protons in the nucleus you rise its pull but since you space only adding electrons come the brand-new shell the shield is not increasing however remains the same all the method across. This way the traction on the electrons being included to the valence covering is boosting steadily all the method across. What wake up if you traction harder top top the electrons? Well, castle come closer come the nucleus and also the dimension of the atom decreases. The effect of the cell core pulling ~ above the electrons gift added throughout a duration is called the effective nuclear charge and is calculated together ZEff = #protons - main point # Electrons.

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



Electronegativity might be the most vital of the regular properties you can learn and also understand since so many other nature are count on that is value. Electronegativity is one atoms capability to traction electrons towards itself.

Electronegativity is normally expressed by the Pauling Scale and also the values were established experimentally. The table below shows the scale values because that the elements.


The electronegativity values rise from left to right and also bottom to height in the regular table excluding the Noble gases. The many electronegative aspect is Fluorine.

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


Ionization Energy

Ionization power is the quantity of energy required to eliminate an electron from an atom. All ionization energies are confident values because all of these removals (even those for facets that form positive ions) need input of energy. The an ext electronegative the element, the higher the ionization eneregy.

See more: What Is The Role Of Tropomyosin In Skeletal Muscles? Chapter 9 ( B) Multiple Choice Flashcards

Electron Affinity

The Electron Affinity that an element is the quantity of energy gained or released with the enhancement of an electron. The electronegativity and also Electron Affinity rises in the same pattern in the regular table. Left come right and bottom come top.