Chapter 5.1 - Electrons and Bonding (electron structure) Flashcards
What are electron shells?
Electron shells are energy levels around an atom’s nucleus, used as a model to visualize the arrangement of electrons.
How does energy relate to electron shells?
The energy of shells increases with their number, referred to as the principal quantum number n.
What is the formula to calculate the maximum number of electrons in a shell?
Numberofelectrons=2n^2, where n is the shell number.
How many electrons can the first four shells hold?
n = 1 –> 2 electrons
n = 2 –> 8 electrons
n = 3 –> 18 electrons
n = 4 –> 32 electrons
What are atomic orbitals?
Atomic orbitals are regions around the nucleus where there is a high probability of finding electrons. Each orbital can hold up to two electrons with opposite spins.
What are the different types of orbitals and their shapes?
s-orbitals: Spherical shape, one orbital per shell.
p-orbitals: Dumbbell shape, three orbitals per shell starting from n=2.
d-orbitals: Complex shapes, five orbitals per shell starting from n=3.
f-orbitals: More complex shapes, seven orbitals per shell starting from n=4.
What is a subshell?
A subshell is a group of orbitals of the same type within a shell.
How many orbitals are found in the s subshell?
1
How many orbitals are found in the p subshell?
3
How many orbitals are found in the d subshell?
5
How many orbitals are found in the f subshell?
7
What is the maximum number of electrons that can be found in the s subshell?
2
What is the maximum number of electrons that can be found in the p subshell?
6
What is the maximum number of electrons that can be found in the d subshell?
10
What is the maximum number of electrons that can be found in the f subshell?
14
What is the order of filling orbitals?
Orbitals fill in order of increasing energy:
1s,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p.
What is important to remember about the 4s and 3d filling and emptying order?
The 4s subshell fills before 3d, but 4s empties before 3d.
Why do electrons pair with opposite spins?
Electrons are negatively charged and repel each other. Pairing with opposite spins minimizes repulsion within an orbital.
What is the rule for filling orbitals within the same subshell?
Electrons occupy orbitals singly first to reduce repulsion, and pairing occurs only when no unoccupied orbital is available.
What is electron configuration? Describe the electronic configuration of the example Krypton.
Electron configuration shows how electrons are distributed among an atom’s subshells. Example:
Kryton (Z=36): 1s^2,2s^2,2p^6,3s^2,3p^6,4s^2,3d^10,4p^6
How is shorthand electron configuration written?
Shorthand uses the previous noble gas and outer subshells.
Write the electronic configuration and the shorthand notation of Li.
1s^2,2s^1 –> [He]2s^1
Write the electronic configuration and the shorthand notation of Na.
1s^2,2s^2,2p^6,3s^1 –> [Ne]3s^1
Write the electronic configuration and the shorthand notation of K.
1s^2,2s^2,2p^6,3s^2,3p^6,4s^1 –> [Ar]4s^1
How do ions affect electron configuration?
Positive ions (cations): Electrons are lost from the outermost shell.
Negative ions (anions): Electrons are added to the outermost shell.
How is the periodic table divided based on electron configuration?
S-block –> left block of 2 groups
P-block –> right block of 6 groups
D-block –> centre block of 10 groups
How are spins shown?
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