Honors Chem Multiple Choice Ch 5

Wave-particle duality

Light and electrons act like both waves and particles.

Photon

One packet of light energy.

Wavelength (λ)

Distance between two crests or two troughs.

Frequency (ν)

Number of wave cycles passing a point each second.

Frequency unit

Hertz (Hz) or 1/s.

Wavelength unit

Meters (m); nanometers (nm) are also used.

Electromagnetic radiation

Energy that travels through space and can travel through a vacuum.

Electromagnetic spectrum

All types of electromagnetic radiation arranged by wavelength.

Electromagnetic spectrum order (longest to shortest wavelength)

Radio, microwave, infrared, visible, ultraviolet, X-ray, gamma ray.

Longest wavelength

Radio waves.

Shortest wavelength

Gamma rays.

Visible light range

400 nm (purple) to 700 nm (red).

Longest visible wavelength

Red.

Shortest visible wavelength

Purple/violet.

Speed of light

3.00 × 10⁸ m/s.

Speed of electromagnetic radiation

All electromagnetic radiation travels at the same speed in a vacuum.

Wavelength and frequency

Inverse relationship: wavelength increases, frequency decreases.

Frequency and photon energy

Direct relationship: frequency increases, photon energy increases.

Wavelength and photon energy

Inverse relationship: wavelength increases, photon energy decreases.

Wave equation

c = λν.

Energy equation

E = hν.

Planck's constant

6.626 × 10⁻³⁴ J·s.

Ground state

Lowest-energy arrangement of electrons.

Excited state

Electron arrangement with more energy than the ground state.

Absorption

An atom takes in energy; an electron moves higher.

Emission

An atom releases a photon; an electron moves lower.

Energy-level diagram

Shows the allowed energy levels of electrons.

Upward arrow

Absorption; energy increases.

Downward arrow

Emission; energy decreases.

Energy gap

Difference between two allowed energy levels.

Continuous spectrum

An uninterrupted range of wavelengths.

Line spectrum

Only certain wavelengths, shown as separate lines.

Atomic emission spectrum

Bright lines produced by excited atoms in a low-density gas.

Spectral line

Represents a photon with a particular wavelength.

Flame test

Uses emitted colors to help identify certain elements.

Bohr model

Electrons are shown in fixed circular orbits with specific energies.

Bohr model limitation

Fixed circular paths do not fully describe electrons.

Wave-like behavior of electrons

Electrons produce diffraction and interference patterns.

Heisenberg uncertainty principle

Exact position and exact momentum cannot both be known at the same time.

Quantum mechanical model

Uses math to describe electron energies and where electrons are likely to be found.

Schrödinger

Developed an equation used in the quantum mechanical model.

Orbital

A 3D region where an electron is most likely to be found.

Pauli exclusion principle

Each orbital holds a maximum of two electrons with opposite spins.

Principal energy level

Main region around the nucleus; labeled n = 1, 2, 3, etc.

Sublevel

Division of an energy level labeled s, p, d, or f.

Energy level structure

Energy level → sublevel → orbital.

Number of sublevels

The number of sublevels equals the principal energy level number (n).

Sublevel energy order

Within the same energy level: s, p, d, f.

s sublevel

1 orbital; holds 2 electrons.

p sublevel

3 orbitals; holds 6 electrons.

d sublevel

5 orbitals; holds 10 electrons.

f sublevel

7 orbitals; holds 14 electrons.

First level with s

n = 1.

First level with p

n = 2.

First level with d

n = 3.

First level with f

n = 4.

Aufbau principle

Fill lower-energy sublevels first.

Hund's rule

Put one electron in each orbital before pairing.

Pauli exclusion principle

Maximum of two electrons per orbital with opposite spins.

Maximum electrons in level 1

2.

Maximum electrons in level 2

8.

Maximum electrons in level 3

18.

Maximum electrons in level 4

32.