Chemistry Quantum Mechanical Model

Imma kms

What is Hunds Rule

Electrons will occupy empty orbitals singly in a given sublevel before pairing up (hotel rooms analogy)

Pauli Exclusion Principle

No two electrons in an atom can have the same set of quantum numbers, meaning each electron must have a opposite spins.

What shape is s orbitals

spheric

What shape is P orbitals

Dumbell

The shape and orientation of orbitals related to what?

The Probability of locating an electron in a certain region around the nucleus

What is the Heisenberg Uncertainty Principle

It states that it is impossible to simultaneously know both the exact position and momentum of an electron

What is Bohrs model

Introduced the concept of fixed orbits where electrons circle the nucleus, which has since been refined into the quantum mechanical model.

What did Heisenbers principle and schrodinger’s equation contribute?

contributed to the modern quantum mechanical model of the atom, which uses probabilities to describe electron positions rather than fixed orbits.

Protons and neutrons are located where?

in the nucleus.

Explain the significance of the quantum numbers for an electron in an atom.

Quantum numbers describe the energy levels, shapes, and directions of spin, providing crucial information about the distribution of electrons within an atom.

Describe the difference between the 2s and 2p orbitals in terms of shape and energy.

The 2s orbital is spherical in shape and has lower energy compared to the 2p orbitals, which have a dumbbell shape and are higher in energy.

Why does the 4s orbital fill before the 3d orbital when filling electron configurations?

The 4s orbital is lower in energy than the 3d orbital. As a result, electrons fill the 4s orbital first before occupying the 3d orbital.

Explain why the 3d orbitals are higher in energy than the 4s orbitals after the 4s orbital fills.

After the 4s orbital is filled, the 3d orbitals become higher in energy because the repulsion between electrons in the 3d orbitals causes them to require more energy than the 4s orbital.

How does the Aufbau principle guide the filling of orbitals in an atom?

The Aufbau principle states that electrons occupy the lowest energy orbitals first before filling higher energy orbitals. This principle helps predict the electron configuration of an atom by guiding the order in which orbitals are filled.

What does the Pauli Exclusion Principle state, and how does it apply to electron configurations?

The Pauli Exclusion Principle states that no two electrons in an atom can have the same set of four quantum numbers. This principle ensures that each orbital can hold a maximum of two electrons with opposite spins

What is Hund's rule, and how does it affect the electron configuration of the p orbitals?

Hund's rule states that electrons will fill degenerate orbitals (orbitals with the same energy, like the p orbitals) singly before pairing up, in order to minimize electron-electron repulsion and maximize the atom's stability.

What is the difference between the ground state and an excited state of an atom?

• The ground state is the lowest energy state of an atom, where electrons are in the lowest available orbitals. The excited state occurs when one or more electrons absorb energy and move to a higher energy orbital.

Why do elements in the same group of the periodic table have similar chemical properties?

Elements in the same group have similar chemical properties due to having the same number of valence electrons, which influences their bonding behavior and reactivity.

What is an atomic orbital, and how does it relate to the concept of electron clouds?

An atomic orbital is a region in an atom where there is a high probability of finding an electron. Electron clouds are representations of these orbitals, showing the regions where electrons are most likely to be found.

How do the first ionization energies of elements change across a period and down a group?

• Ionization energy increases across a period (from left to right) because the effective nuclear charge increases, making it harder to remove an electron. Ionization energy decreases down a group because the outer electrons are farther from the nucleus and experience more shielding.

What is the shape of an s orbital and how does it differ from the shape of a p orbital

An s orbital has a spherical shape, while a p orbital has a dumbbell shape. The p orbital also has directional properties, whereas the s orbital is isotropic.

What is the significance of the principal quantum number (n)?

• The principal quantum number (n) determines the energy level and size of an orbital. As n increases, the orbital becomes larger and the energy of the electron increases.

How does the electron configuration of an atom relate to its chemical reactivity

The electron configuration, particularly the number of valence electrons, determines how an atom will react chemically. Atoms with incomplete valence shells tend to form bonds to achieve a stable electron configuration.

Describe the concept of electron shielding and its effect on atomic size.

Electron shielding occurs when inner electrons partially block the attraction of the nucleus for outer electrons. As a result, the effective nuclear charge felt by outer electrons is reduced, causing the atomic size to increase as you move down a group.