Atomic Structure and Periodicity - Chapter 2 (Zumdahl, CHEMISTRY: An Atoms First Approach, 3rd Edition)

A set of practice flashcards covering key concepts from Section 2: Atomic Structure and Periodicity, including electromagnetic radiation, quantum mechanics, atomic orbitals, and periodic trends.

What is the speed of light?

2.9979 × 10^8 m/s.

What is the fundamental relation between wavelength and frequency for electromagnetic radiation?

c = λν, so ν = c/λ and λ = c/ν.

What are the visible-light wavelength ranges for red and blue colors?

Red: approximately 700–635 nm; Blue: approximately 490–450 nm.

How is photon energy calculated from frequency and wavelength?

E = hν = hc/λ, where h is Planck’s constant.

What is Planck’s constant and its value?

h = 6.626 × 10^-34 J·s.

What is De Broglie’s equation for the wavelength of a particle?

λ = h/(mv) where m is mass and v is velocity.

What equation relates the energy change in a transition to the emitted/absorbed photon?

ΔE = Efinal − Einitial; the photon energy equals |ΔE| and λ = hc/|ΔE|.

What is the Bohr energy level expression for hydrogen-like atoms?

E_n = −2.178 × 10^−18 J × Z^2 / n^2.

Why do hydrogen emission spectra indicate quantized energy levels?

Because only certain transitions produce photons of specific wavelengths, showing discrete energy levels.

What is the Bohr model’s significance for hydrogen?

It correctly describes discrete energy levels and explains the hydrogen emission spectrum.

What is the wave function in quantum mechanics and what does |ψ|^2 represent?

ψ is the wave function; |ψ|^2 gives the probability density of finding an electron at a point.

What does Heisenberg’s Uncertainty Principle state?

Δx Δp ≥ h/4π, indicating limits on simultaneous precision of position and momentum.

What are the four quantum numbers and what does each represent?

n: principal (size/energy); l: azimuthal (shape, 0 to n−1); ml: magnetic (orientation, −l to +l); ms: spin (±1/2).

What does the Pauli exclusion principle state?

No two electrons in an atom can have the same set of four quantum numbers; an orbital holds at most two with opposite spins.

What is Hund’s rule?

For degenerate orbitals, electrons occupy them singly with parallel spins to minimize energy.

What are s, p, d, and f orbitals and their general shapes or labels?

s: spherical (l=0); p: two lobes (l=1); d: four lobes (l=2); f: more complex shapes (l=3). Labels follow the axis and l value.

What is the Penetration effect in polyelectronic atoms?

A 2s electron penetrates closer to the nucleus and is more strongly attracted than a 2p electron, making 2s lower in energy.

What are polyelectronic atoms?

Atoms with more than one electron; electron–electron repulsion affects orbital energies.

What is the Aufbau principle?

Electrons fill orbitals in order of increasing energy, building up from lowest-energy orbitals.

What is the electron configuration of neon (Ne) as given in the notes?

Ne: 1s^2 2s^2 2p^6.

What are valence electrons?

Electrons in the outermost principal quantum level; determine chemical behavior; elements in the same group share valence configurations.

What is the difference between covalent radii and metallic radii?

Covalent radii are based on covalent bonds; metallic radii are half the distance between adjacent metal atoms in a solid.

How does atomic radius trend across a period and down a group?

Across a period: decreases; Down a group: increases.

What is ionization energy?

Energy required to remove an electron from a gaseous atom or ion in its ground state.

What is the trend of first ionization energy across a period and down a group?

Increases across a period; decreases down a group.

What is the typical relationship between the first and second ionization energies?

I1 is generally smaller than I2; removing a second electron requires more energy.

What is the hydrogen emission spectrum, and why is it important?

A line spectrum showing discrete wavelengths; indicates quantized energy levels in the hydrogen atom.

What is a line spectrum versus a continuous spectrum?

Line spectrum has discrete wavelengths; continuous spectrum contains all wavelengths (white light).

What is de Broglie wavelength used to describe in quantum mechanics beyond electrons?

Wave-particle duality; all matter exhibits wave-like properties with λ = h/(mv).

What is a radial probability distribution in atomic orbitals?

A graph of the total probability of finding an electron at a distance r from the nucleus; shows where electron density is likely.

What is a probability density map (electron density map)?

A diagram showing the probability distribution of finding an electron in space; darker regions indicate higher probability.

What is the orbital diagram and an example with neon?

A schematic showing electrons in orbitals (e.g., Ne: 1s^2 2s^2 2p^6).