CHEM 201 - Relative Energies of Orbitals and Electronic Configuration

Flashcards covering key concepts from CHEM 201 lecture notes on relative energies of orbitals, electronic configuration, quantum numbers, and periodic table trends.

What are the subshells found in the n=1 shell?

1s

What are the subshells found in the n=2 shell?

2s, 2p

What are the subshells found in the n=3 shell?

3s, 3p, 3d

How do ns orbitals generally compare in energy as 'n' increases?

Increasing energy: 1s < 2s < 3s < 4s

How do np orbitals generally compare in energy as 'n' increases?

Increasing energy: 2p < 3p < 4p

In a hydrogen atom, what is true about the energy of all orbitals within a given shell 'n'?

All orbitals in a given shell 'n' have the same energy.

How do the relative energies of subshells compare within a given shell 'n' for multi-electronic atoms (e.g., n=3)?

3s < 3p < 3d, where energy is influenced by the azimuthal quantum number (l).

What is the general energy relationship between the 4s and 3d subshells in multi-electronic atoms?

E 4s < E 3d

What is meant when an electron 'occupies the orbital'?

It means the electron wave adopts a specific energy level.

What are the two possible values for the spin quantum number (ms)?

+1/2 and -1/2

What does it mean when electrons are said to behave like 'tiny magnets'?

Electrons can spin in two different directions, creating magnetic fields in opposite directions.

According to the Pauli Exclusion Principle, what is the maximum number of electrons that can occupy a single orbital?

Two electrons.

What condition must be met for two electrons to occupy the same orbital?

They must have opposite spins, making them 'spin-paired'.

What is the maximum number of electrons a 'p' subshell can hold?

6 electrons (3 orbitals x 2 electrons/orbital).

What is the maximum number of electrons a 'd' subshell can hold?

10 electrons (5 orbitals x 2 electrons/orbital).

What is the maximum number of electrons that can be held in the n=3 shell?

18 electrons (2 in 3s, 6 in 3p, 10 in 3d).

Which groups are collectively known as the Main Group Elements?

Groups 1A-8A

Which group of elements is known for forming bases or alkaline solutions when reacting with water?

Group 1A, the Alkali metals (excluding Hydrogen).

What is the common name for elements in Group 7A?

Halogens, meaning 'salt forming'.

What is 'electronic configuration'?

The distribution of electrons among orbitals of an atom.

How is the electron population in a subshell indicated in electronic configuration notation?

With a superscript (e.g., 1s^2 means two electrons in the 1s subshell).

What principle states that electrons are added one at a time to available orbitals with the lowest energy first?

The Aufbau principle.

What does Hund's Rule state regarding electrons in degenerate orbitals?

When electrons are placed in a set of orbitals of equal energy, they are spread out as much as possible to give the maximum number of unpaired electrons.

What characterizes an atom in an 'excited state'?

It has one or more electrons in orbitals which are not in the lowest energy state, meaning it does not follow the Aufbau, Pauli, and/or Hund's rules.

How do 'd' orbitals fill up in relation to their period number on the periodic table?

The 'd' orbitals fill up in levels 1 less than the period number (e.g., 3d fills in Period 4).

Why is the electronic configuration of Chromium (Cr) an exception to the general filling rules?

Cr's configuration is [Ar] 4s1 3d5 because a half-filled d-orbital is energetically more stable.

Why is the electronic configuration of Copper (Cu) an exception to the general filling rules?

Cu's configuration is [Ar] 4s1 3d10 because a completely-filled d-orbital is energetically more stable.

What type of magnetic material has all its electrons paired and is weakly repelled by a magnet?

Diamagnetic material.

What type of magnetic material contains unpaired electron(s) and is attracted by an external magnetic field?

Paramagnetic material.

When would an 'orbital box diagram' be particularly useful?

When interested in the spin of electrons and magnetic properties such as unpaired electrons.