Quantum numbers and electron configurations

The three rules that dictate the manner in which electrons are filled in atomic orbitals are:

• Electron configuration rule: Predicting the properties of a group of elements (elements with similar electron configurations tend to exhibit similar properties).

• Hund’s rule: All the subshells in an orbital must be singly occupied before any subshell is doubly occupied. Furthermore, the spin of all the electrons in the singly occupied subshells must be the same (in order to maximize the overall spin).

• Pauli’s exclusion principle: states that no two electrons can have equal values for all four quantum numbers. Consequently, each subshell of an orbital can accommodate a maximum of 2 electrons and both these electrons MUST have opposite spins.

• The Aufbau principle: electrons must completely fill the atomic orbitals of a given energy level before occupying an orbital associated with a higher energy level. Electrons occupy orbitals in the increasing order of orbital energy level.

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According to the Aufbau Principle, which sublevel should starting filling with electrons before the 3p sublevel?

• 3s
• 2p
• 4s
• 4p

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What is the electron configuration for F?

• 1s2 2s2 3p5
• 1s2 2s2 3d5
• 1s2 2s2 2p5
• 1s2 2p5

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How many electrons can the first energy level hold?

• 1
• 2
• 8
• 0

How many quantum numbers are needed to describe the energy state of an electron in an atom?

• 1
• 2
• 3
• 4

How many electrons can be found in a p orbital?

• 2

• 3

• 4

• 6

How many d orbitals are there in a given sublevel?

• 1
• 3
• 5
• 7

How many p orbitals are there in a sublevel?

• 2
• 1
• 4
• 3

How can you tell how many energy levels an atom has? 

• By the Group

• By the Period

• By the atomic mass

• By the atomic number

Which element is represented by this orbital notation?

• carbon

• nitrogen

• oxygen

• fluorine

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