An electron configuration is a method of indicating the arrangement of electrons about a nucleus. A typical electron configuration consists of numbers, letters, and superscripts with the following format:
The coefficient is the first number indicates the energy level.
The lowercase letter indicates the type of orbital (s, p, d, or f).
A superscript indicates the number of electrons in the orbital.
Example: 1s2 means that there are two electrons in the ‘s’ orbital of the first energy level. The element is helium (He).
To write a longhand electron configuration:
Begin on the upper-left-most position of the periodic table (1st energy level, s orbital) and begin moving across and down the table.
Use the Aufbau principle to fill in electrons in each orbital. The Aufbau process requires that electrons fill the lowest energy orbitals first. In another words, atoms are built from the ground upwards.
The sum of the superscripts should equal the total number of electrons.
Example: Mg 1s2 2s2 2p6 3s2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Question 16
16.
How many electrons can each orbital hold:
s _______
p _______
d _______
f _______
1
1
1
Noble Gas Electron Configuration
A "shorthand" version of electron configurations. It uses the group 18 (noble gases) elements as "place markers" that are then followed by the last energy level for the atom in question.
Noble Gases - group 18 elements (the far-right-most column) - He, Ne, Ar, Kr, Xe, and Rn.
Brief Instructions:
Locate the atom on the periodic table.
Identify the prior noble gas (the one that is just prior the atom in question; up one row and to the far-right).
Record that noble gas in brackets - example [He].
Record the electron configuration that exists in the last energy level (the row just after the noble gas) of the atom in question.
Example - Iron (Fe)
Longhand Configuration for Iron (Fe): 1s2 2s2 2p6 3s2 3p6 4s2 3d6
Noble Gas Configuration for Iron (Fe): [Ar] 4s2 3d6
How to type brackets (see image below - do not use "shift")
Construct a longhand and noble gas (shorthand) configuration for each of the following:
Question 1
1.
Na (sodium)
Longhand _______
Noble Gas _______
Question 2
2.
Pd (palladium)
Longhand _______
Noble Gas _______
Question 3
3.
W (tungsten)
Longhand _______
Noble Gas _______
Question 4
4.
N (nitrogen)
Longhand _______
Noble Gas _______
Question 5
5.
Ag (silver)
Longhand _______
Noble Gas _______
Question 6
6.
Ti (titanium)
Longhand _______
Noble Gas _______
Question 7
7.
Sr (strontium)
Longhand _______
Noble Gas _______
Question 8
8.
Cs (cesium)
Longhand _______
Noble Gas _______
Question 9
9.
Cl (chlorine)
Longhand _______
Noble Gas _______
Question 10
10.
Hg (mercury)
Longhand _______
Noble Gas _______
Identify the atom that each notation represents:
Use the element abbreviation for each.
Question 11
11.
Identify the element:
[Kr] 5s2 4d10 5p3 _______
Question 12
12.
Identify the element:
[Kr] 5s2 4d10 5p6 _______
Question 13
13.
Identify the element:
[Ar] 4s1 _______
Question 14
14.
Identify the element:
[Xe] 6s2 4f14 5d7 _______
Question 15
15.
Identify the element:
[Ne] 3s2 3p1 _______
Question 17
17.
Question 18
18.
Question 19
19.
Preview question: How many electrons are in the outermost energy level of this atom:
[Xe] 6s2 5d10 6p4
_______
Select which orbitals would exist in the 3rd energy level (select all that apply):
p
f
s
d
Select which orbitals would exist in the 4th row on the periodic table (select all that apply):