Review of Electromagnetic Spectrum, Quantum Mechanics, and Molecular Chemistry

These flashcards cover key concepts related to the electromagnetic spectrum, quantum mechanics, molecular chemistry, bonding theories, and trends in the periodic table.

What is the electromagnetic spectrum?

The range of all types of electromagnetic radiation, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

What is wavelength?

The distance between identical points on successive waves, usually measured in meters (m), nanometers (nm), or angstroms (Å).

What is frequency?

The number of wavelengths that pass through a particular point in one second, measured in Hertz (Hz).

What is the visible light wavelength range?

Approximately from 400 nm (violet) to 700 nm (red).
violet→blue→green→yellow→orange→red

What relationship exists between wavelength and frequency?

inversely proportional; as one increases, the other decreases.

What is the equation for calculating energy of a photon?

E = hν, where E is energy, h is Planck's constant (6.63 × 10^-34 J·s), and ν is frequency.

What is the photoelectric effect?

The phenomenon where electrons are emitted from a metal surface when light of a certain frequency shines on it.
When light shines on a metal, electrons are ejected, like tiny particles being knocked off. This happens because light, in this case, acts like a stream of tiny energy packets (photons) that transfer energy to electrons, allowing them to escape the metal's surface.

Define energy level in the context of the Bohr model.

Quantized orbits around the nucleus where electrons can exist without losing energy.
They are like specific floors in a building where electrons can reside, with the lowest floor (closest to the nucleus) having the least energy, and higher floors (further from the nucleus) having more energy.

What are the four quantum numbers?

Principal (n), Azimuthal (l), Magnetic (ml), and Spin (ms).

What is the Pauli Exclusion Principle?

No two electrons in the same atom can have the same set of four quantum numbers.

What is the primary characteristic of paramagnetic materials?

They have one or more unpaired electrons making it weakly attracted to magnetic fields.

What does a Lewis dot structure represent?

A diagram that shows the bonding between atoms of a molecule and the lone pairs of electrons that may exist.

What determines bond polarity in a molecule?

Differences in electronegativity between the bonded atoms, with larger differences leading to more polar bonds.
Electronegativity differences cause variability in shared electron distribution.
It’s also about how strongly one atom pulls shared electrons in a bond, is determined by the difference in electronegativity between the two atoms involved.

What is VSEPR theory?

a model that predicts the shape of a molecule. It's based on the idea that electron pairs repel each other, and arrange themselves to minimize repulsion.

What describes metallic bonding?

the way that metal atoms are kept together within a metal material. A metallic bond is a type of chemical bond similar to a covalent bond. Atoms in metals are held together by forces caused by the valence electrons. A bonding model where electrons are delocalized across a lattice of metal atoms, creating an 'electron sea' that allows conductivity. They’re strong and have high boiling/melting points

How do bond lengths and bond strengths relate?

shorter bond lengths generally mean stronger bonds, and longer bonds are weaker, because atoms are closer together when bonded and more electrons are shared between the bonded atoms, resulting in a stronger attraction but shorter bond.

What is the significance of constructing orbital diagrams?

They visually represent the distribution of electrons in orbitals and help predict bonding and stability of molecules. Also helps us understand how atoms interact and form bonds, which is crucial for understanding chemical reactions and the properties of elements

Explain what happens in a covalent bond.

Atoms share electrons to achieve full outer electron shells, often resulting from overlapping atomic orbitals.

What is the trend of ionization energy across a period in the periodic table?

increases

What is electron affinity?

The amount of energy released when an electron is added to a neutral atom in a gaseous state (gaseous atom) and forms a negative ion.

Describe the significance of resonance structures.

They happen when there are multiple, correct Lewis structures for a molecule, and are important for understanding molecular stability and reactivity, indicating that the actual structure is a hybrid of these resonance forms.