The electronic structure of atoms

Chemistry Module The principle quantum number (n) correlates to “ shell number”, or the size (roughly) of an orbital. What do the other three quantum numbers (l, m, and ms) correlate to?
Azimuthal quantum number ‘ l’ is second quantum number that describes the unique quantum state of an electron. It determines orbital angular quantum. It also determines the shape of the orbital. Magnetic quantum number is a whole number that describes the orientation of an orbital in space with respect to magnetic field. Spin quantum number ‘ ms’ is related to spin of the electron that can be either clockwise or anticlockwise. Its value is +1/2 or -1/2 (Quantum Numbers and Electron Configurations, 2014).
2. How many different subshells are there within shell 3? What are they?
Shell 3 contains three subshells which are 3s, 3p and 3d.
3. How many different orbitals (orientations) are there within the d subshell? How many total electrons fit in the d subshell?
There are five possible orientations in the d subshell. Three of them are between x, y and z-axis and other two are on the axis. Total number of electron that can accommodate into d subshell are ten.
4. What does the Aufbau Principle state?
Aufbau is a German word that means ‘ building up’. According to this principle, electron are filled in shells of the atom that they get most stabilized. The electron are filled in increasing order of orbitals energy.
5. What does Hund’s rule state? Explain why the electron diagram (orbital diagram) of carbon demonstrates Hund’s Rule.
Hund’s rule states that if orbitals of equal energy are available to electrons, then the electrons prefer to fill them in unpaired form before pairing. It gives maximum positive spin number to electrons.
There are six electron in carbon. Two are present in 1s orbital, 2s contain two electron and there are two unpaired electrons in 2p orbital. The energy difference between 2s and 2p orbitals is small due to which one electron from 2s is shifted to third empty 2p orbital and then carbon makes four bonds in its compounds.
6. What does the Pauli Exclusion Principle state?
The Pauli Exclusion Principle states that no two electron in an atom can have all same quantum number values. If there are two electron with same principle quantum number, azimuthal quantum and magnetic quantum number then they will have opposite spin quantum numbers. They will be paired with opposite spins.
7. How many electrons TOTAL can fit into shell 3?
2n2 formula is used to know the number of electron in a shell number. For shell 3, value of n is 3, so total number of electrons is 18 that can fit into this shell.
8. What does the term “ octet” refer to?
The term octet refers to the concept that an atom of main group gets highest stability when it has 18 electrons its outermost shell.
9. Which orbital fills first, 4s or 4p?
4s orbital is filled firstly because both have same number of shell number but the azimuthal quantum number for s is lower than p, so 4s is firstly filled followed by 4p orbital.
10. Which orbital fills first, 4s or 3d?
4s is orbital is filled firstly. Because n+l value for 4s is 4= 1= 4, while for 3d, it is 3+2= 5. Here n+l rule is followed according to which, orbitals with lower value of n+l are filled firstly and they are lower in energy.
11. What is the electron configuration (longhand) of S? Of O?
S= 1s2, 2s2, 2p6, 3s2, 3p4
O= 1s2, 2s2, 2p4
12. What would an orbital diagram of S look like? (separate out the p orbitals) Of O?
1s2 electrons are lowest in energy. And 3p4 electrons are highest in energy.
13. What is the electron configuration (shorthand) of S? Of O?
S= 1s2, 2s2, 2p6, 3s2, 3p4
O= 1s2, 2s2, 2p4
14. You are familiar with the principle that atoms react similarly to other atoms in their
Group. Based upon the above, speculate as to WHAT SPECIFIC physical characteristic
Of a pair of atoms (such as S and O) might result in this similarity.
They show many properties in same manner. Their compounds can be gas solid or liquid with same reacting species.
15. Write out longhand and shorthand configurations for the following:
Long-hand version: 1s2
Short-hand version: [He]
Longhand: 1s2 2s2 2p6 3s2 3p6
Shorthand: [Ar]
Longhand: 1s2 2s2 2p6 3s2 3p6
Shorthand: [Ne] 3s2 3p6
Shorthand: [Ar]
Longhand: 1s2, 2s2, 2p6, 3s2, 3p6
Longhand: 1s2 2s2 2p6 3s2 3p6 3d5
Shorthand: [Ar] 3d5
Long hand: 1s2 2s2 2p6 3s2 3p6 4s1 3d5
Short hand: [Ar] 4s2 3d4
Long hand: 1s2 2s2 2p6 3s2 3p6 4s1 3d10
Shorthand: [Ar] 4s1 3d10
Quantum Numbers and Electron Configurations. (2014). Retrieved from http://chemed. chem. purdue. edu/