Electron Configurations Beyond Neon (8.1.4) Flashcards
• Each orbital holds two electrons, the s orbital for a given energy level is lower in
energy than the p orbitals, and one electron enters each degenerate orbital
before any pairing occurs.
• Each orbital holds two electrons, the s orbital for a given energy level is lower in
energy than the p orbitals, and one electron enters each degenerate orbital
before any pairing occurs.
• By the aufbau principle, the ground state electron configurations for atoms
beyond hydrogen are found by filling orbitals in successive order.
• By the aufbau principle, the ground state electron configurations for atoms
beyond hydrogen are found by filling orbitals in successive order.
• The periodic table is arranged in blocks of elements with similar valence
electron configurations.
• The periodic table is arranged in blocks of elements with similar valence
electron configurations.
By the Pauli exclusion principle, each orbital can
only hold two electrons. The two electrons differ
only in electron spin quantum number (ms).
For a given energy level in elements beyond
hydrogen, the s orbital is lower in energy than the
p orbitals. This is due to electron shielding. The
s orbital therefore fills before the p orbitals.
By Hund’s rule, one electron enters each
degenerate orbital (such as the 2p orbitals) before
any pairing occurs. These electrons tend to have
aligned electron spins.
By the aufbau principle, the ground state electron
configurations for atoms beyond hydrogen are found
by filling orbitals in successive order, from lowest
energy to highest energy.
The electron configuration for neon (Ne) is
1s2
2s2
2p6
. This is referred to as the neon core, and
is represented by [Ne] in the electron configuration
for elements beyond neon. Similarly, the electron
configuration for argon is called the argon core
([Ar]).
Due to electron shielding, the 4s orbital is lower in
energy than the 3d orbitals for most elements.
Therefore, the 4s orbital fills before the 3d orbitals.
For example, the 4s orbital of scandium (Sc) fills
before the 3d orbital. Therefore, the electron
configuration of scandium is [Ar]4s2
3d1
.
By the Pauli exclusion principle, each orbital can
only hold two electrons. The two electrons differ
only in electron spin quantum number (ms).
For a given energy level in elements beyond
hydrogen, the s orbital is lower in energy than the
p orbitals. This is due to electron shielding. The
s orbital therefore fills before the p orbitals.
By Hund’s rule, one electron enters each
degenerate orbital (such as the 2p orbitals) before
any pairing occurs. These electrons tend to have
aligned electron spins.
By the aufbau principle, the ground state electron
configurations for atoms beyond hydrogen are found
by filling orbitals in successive order, from lowest
energy to highest energy.
The electron configuration for neon (Ne) is
1s2
2s2
2p6
. This is referred to as the neon core, and
is represented by [Ne] in the electron configuration
for elements beyond neon. Similarly, the electron
configuration for argon is called the argon core
([Ar]).
Due to electron shielding, the 4s orbital is lower in
energy than the 3d orbitals for most elements.
Therefore, the 4s orbital fills before the 3d orbitals.
For example, the 4s orbital of scandium (Sc) fills
before the 3d orbital. Therefore, the electron
configuration of scandium is [Ar]4s2
3d1
.
The periodic table is arranged in blocks of elements
with similar valence electron configurations.
The s block consists of elements in groups 1 and 2
on the periodic table, as well as helium. The s block
is characterized by having valence electrons in
s orbitals.
The p block consists of elements in groups 13
through 18 on the periodic table, and is
characterized by having valence electrons in
p orbitals.
The d block consists of elements in groups 3
through 12 on the periodic table, and is
characterized by having valence electrons in
d orbitals.
The f block consists of the lanthanide series and
the actinide series. The f block is characterized by
having valence electrons in f orbitals.
The periodic table is arranged in blocks of elements
with similar valence electron configurations.
The s block consists of elements in groups 1 and 2
on the periodic table, as well as helium. The s block
is characterized by having valence electrons in
s orbitals.
The p block consists of elements in groups 13
through 18 on the periodic table, and is
characterized by having valence electrons in
p orbitals.
The d block consists of elements in groups 3
through 12 on the periodic table, and is
characterized by having valence electrons in
d orbitals.
The f block consists of the lanthanide series and
the actinide series. The f block is characterized by
having valence electrons in f orbitals.
What is the maximum number of electrons in a 3d set of orbitals?
10 (C)
A d energy sublevel (regardless of whether it is 3d or any other d energy sublevel) contains five orbitals. Each orbitals contains two electrons, so the maximum number of electrons contained in a 3d energy sublevel is ten.
Which of the following is a p block element?
sulfur (C)
Sulfur is a p block element.
Which of the following is the best explanation of why the orbital of the 4s energy sublevel is, in general, lower than the orbitals of the 3d energy sublevel in electron orbital filling following the aufbau principle?
The orbital in the 4s energy sublevel experiences less electron shielding, and thus experiences a greater degree of effective nuclear charge than the 3d orbitals. (C)
The orbital of the 4s energy sublevel is, in general, lower in energy than the orbitals of the 3d energy sublevel because electrons in the 4s orbital can exist part of the time inside the n = 3 energy level.
What is the ground state electron configuration of manganese?
[Ar] 4s^2 3d^5 (C)
This is the correct ground state electron configuration for manganese.
What is the electron configuration of sodium ion (Na+ )?
[ Ne] (A)
Sodium ion has one less electron than neutral sodium. Therefore, it has the same electron configuration as neon.
Which of the following best illustrates the aufbau principle?
Electrons filling up existing orbitals in an expected arrangement (C)
The aufbau principle is the “building up” of an atom by the arrangement of the electrons in existing orbitals. The electrons exist in the orbitals of the lowest energy available and fill following Hund’s rule, thereby not violating the Pauli exclusion principle.
What is the ground state electron configuration of aluminum?
[ Ne] 3s^2 3p^1 (B)
This is the correct ground state electron configuration of aluminum.
Which of the following is the best electron configuration of a gaseous sample of chromium?
Cr: [Ar] 4s^1 3d^5 (D)
This electron configuration provides the correct number of electrons and both the s energy sublevel and the d energy sublevel are half-filled. This is the most stable configuration.
Which of the following represents the ground state electron configuration of a neutral calcium atom?
Ca: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 (C)
This is the correct ground state electron configuration for an atom of calcium. A neutral atom of calcium has 20 electrons.
What is the ground state electron configuration of scandium?
[Ar] 4s^2 3d^1 (A)
This is the correct ground state electron configuration of scandium.
