Modern Atomic Theory Test

Heat vs Temp

Heat: The total energy of molecular motion in a substance (joules/calories)

Temp: the average energy of that motion ( Celsius, Fahrenheit, or Kelvin)

Specific Heat Capacity

A measurement of a materials ability to absorb heat.

Measures the heat energy required to raise the temperature of one unit mass of a substance by one degree Celsius.

Measured in (J/kg°C).

Law of Conservation of Energy

Energy cannot be created or destroyed, only transformed from one form to another.

Light Equation (E=hc/λ)

The equation relates the energy (E) of a photon to its wavelength (λ). Here, h is Planck's constant (6.626 × 10⁻³⁴ J·s), c is the speed of light (3.00 × 10⁸ m/s), and λ is the wavelength in meters. The equation shows that energy is inversely proportional to wavelength: shorter wavelengths have higher energy.

Photoelectric Effect

The phenomenon where electrons are emitted from a material (typically a metal) when it absorbs light of sufficient energy. This effect demonstrates that light can behave as both a wave and a particle (photon), and it provided evidence for the quantum nature of light. The emitted electrons' energy depends on the light's frequency, not its intensity.

Bohr Model

Describes the atom as having a central nucleus with electrons orbiting in fixed paths or energy levels. Electrons can only occupy certain allowed orbits, and they gain or lose energy by jumping between these levels, emitting or absorbing photons.

Bright Line Emission Spectra

Unique patterns of light emitted by atoms when they transition from a higher energy state to a lower one. These serve as a "fingerprint" for identifying elements and understanding their electronic structure.

Limitations of Bohr Model

Cannot explain spectra of multi-electron atoms.

Assumes fixed orbits, neglecting electron wave nature.

Fails to account for electron spin and relativistic effects.

Does not explain the Zeeman and Stark effects.

Inadequate for predicting chemical behavior of atoms.

Limited to hydrogen-like systems only.

Quantum Mechanical Model

describes the behavior of electrons in atoms using quantum mechanics. Replaces the classical notion of fixed orbits with probabilistic electron clouds, where the precise position and momentum of an electron cannot be simultaneously known.

De Broglie

Introduced the idea that every moving particle has an associated wavelength

Heisenberg

Developed the uncertainty principle, stating that certain pairs of physical properties cannot be simultaneously known with arbitrary precision.

Schrödinger

contributed significantly to the understanding of wave functions and superposition in quantum theory.

Aufbau Principle

States that electrons occupy the lowest available energy levels first. This principle helps explain the electron configuration of elements, ensuring stability by minimizing energy.

Hund’s Rule

In a given subshell, electrons will occupy empty orbitals singly before pairing up in the same orbital. This minimizes electron-electron repulsion and leads to a more stable arrangement. It is essential for predicting electron configurations in atoms.

Pauli Exclusion Principle

This principle states that no two electrons can occupy the same quantum state simultaneously within a quantum system.

Electrons that are in the same orbital move opposite directions (CCW/CW)

Kinetic Energy

Energy of motion; depends on mass and speed.

Potential Energy

Stored energy based on position or state; gravitational and elastic are common forms.

Thermal Energy

Energy related to temperature; results from the movement of particles.

Chemical Energy

Energy stored in chemical bonds; released during reactions.

Electrical Energy

Energy from electric charges; powers devices and systems.

Nuclear Energy

Energy stored in atomic nuclei; released during nuclear reactions.

Mechanical Energy

Sum of kinetic and potential energy in an object.

Red

620–750 nm

Orange

590–620 nm

Yellow

570–590 nm

Green

495–570 nm

Blue

450–495 nm

Indigo

425–450 nm

Violet

380–425 nm

s orbital

Circle shape

p orbital

hourglass

d orbital

x shaped