# Atomic Structure, Periodic Trends & Chemical Bonding > 32 chemistry review cards on atomic structure, quantum numbers, electron configuration, periodic trends, chemical bonding, Lewis structures, VSEPR geometry, hybridization, and intermolecular forces. Covers general-chemistry theory rather than a 1–118 element-by-element directory. - **Canonical URL:** https://flashcards.world/flashcards/sets/fa6cff7c-4727-423a-a99e-e8c2592eac6b/ - **Markdown URL:** https://flashcards.world/flashcards/sets/fa6cff7c-4727-423a-a99e-e8c2592eac6b.md - **Level:** basic - **Languages:** en → en - **Total Cards:** 32 ## Flashcards (32 Cards) | # | Front (Term / Prompt) | Back (Definition / Answer) | Example | Multiple-Choice Options | | :--- | :--- | :--- | :--- | :--- | | 1 | How do resonance contributors relate to the actual structure? | They differ in electron placement, not atom positions or connectivity. The actual structure is a resonance hybrid, not molecules switching between drawings. | | | | 2 | Which Lewis structures illustrate an incomplete and an expanded octet? | BF₃ has six electrons around B; SF₆ has twelve around S in their usual Lewis structures. | | | | 3 | How does Hund's rule fill equal-energy orbitals within a subshell? | Place one electron in each orbital with parallel spins before pairing electrons. | | | | 4 | How does VSEPR explain water's H–O–H angle of about 104.5°? | Oxygen's two lone pairs repel more strongly than bonding pairs, compressing the angle below the ideal tetrahedral 109.5° in this model. | | | | 5 | What does effective nuclear charge Z_eff represent? | The net positive nuclear charge felt after electron shielding. A simple model writes Z_eff = Z − S, where S represents shielding. | | | | 6 | How does the electron-sea model explain metallic bonding and conduction? | Positive ion cores are bound by delocalized valence electrons. An electric field produces a net electron drift, allowing electrical conduction. | | | | 7 | How do σ and π bonds differ in orbital overlap? | A σ bond has overlap along the internuclear axis. A π bond has lateral overlap, commonly between parallel unhybridized p orbitals in introductory examples. | | | | 8 | What is the general atomic-radius trend across a period and down a group? | Radius generally decreases left to right as effective nuclear attraction grows, and increases down a group as new electron shells are added. | | | | 9 | What makes two atoms isotopes of the same element? | They have the same number of protons but different numbers of neutrons. | | | | 10 | What does VSEPR use to predict geometry around a central atom? | Electron domains arrange to reduce repulsion. Each bond, single or multiple, counts as one domain; each lone pair also counts as one. | | | | 11 | How is an atom's formal charge calculated in a Lewis structure? | FC = V − N − B/2: V is the free neutral atom's valence-electron count, N its nonbonding electrons and B its bonding electrons. | | | | 12 | Which families occupy groups 1, 2, 17 and 18 of the periodic table? | Group 1 except hydrogen: alkali metals; group 2: alkaline earth metals; group 17: halogens; group 18: noble gases. | | | | 13 | What is first ionization energy, and what is its usual trend across a period? | The energy needed to remove an electron from a neutral gaseous atom in its ground state. It generally rises left to right, with exceptions. | | | | 14 | What is electron affinity when defined as the energy change for electron attachment? | It is ΔE for X(g) + e⁻ → X⁻(g). Negative values mean energy is released; halogens generally have strongly negative values in this convention. | | | | 15 | Why is boron's first ionization energy lower than beryllium's? | B loses a higher-energy, less penetrating 2p electron; Be loses a 2s electron. The 2p electron is easier to remove. | | | | 16 | What causes London dispersion forces, and what tends to strengthen them? | Electron-cloud fluctuations create correlated temporary dipoles. Greater polarizability and surface contact generally strengthen attraction; molar mass alone is insufficient. | | | | 17 | What is electronegativity, and which element is highest on the Pauling scale? | A bonded atom's ability to attract shared electrons. Fluorine is highest, with a Pauling value of 3.98. | | | | 18 | How reliably does electronegativity difference classify bond type? | Larger differences usually mean more polar bonding. Numerical cutoffs between nonpolar, polar and ionic bonding are rough guidelines with exceptions. | | | | 19 | How many σ and π bonds form the carbon–carbon triple bond in ethyne? | One σ bond and two mutually perpendicular π bonds. | | | | 20 | What molecular shape does VSEPR predict for XeF₄? | Square planar. Its six electron domains have an octahedral arrangement, with two lone pairs opposite each other. | | | | 21 | What do the four quantum numbers n, ℓ, mℓ and ms describe in the orbital model? | n labels the shell, ℓ the subshell, mℓ the orbital orientation and ms the spin projection (+½ or −½). | | | | 22 | What does the Pauli exclusion principle imply for an atomic orbital? | At most two electrons can occupy it, with opposite spin projections. No two electrons in an atom share all four quantum numbers. | | | | 23 | Which donor and acceptor groups commonly form strong intermolecular hydrogen bonds? | In common introductory examples, H bonded to N, O or F interacts with an available lone pair on N, O or F in another molecule. This pattern is not an exhaustive definition. | | | | 24 | How does the Aufbau guideline construct a ground-state electron configuration? | Fill lower-energy orbitals first. The simple filling order has exceptions, especially among transition metals. | | | | 25 | What are ammonia's electron-domain and molecular geometries? | NH₃ has four electron domains: three bonds and one lone pair. The domain geometry is tetrahedral; the molecular shape is trigonal pyramidal. | | | | 26 | Where are protons, neutrons and electrons in an atom, and what are their charges? | Protons (+e) and neutrons (0) are in the nucleus; electrons (−e) occupy the surrounding electron cloud. e is the elementary charge. | | | | 27 | In the simple hybrid-orbital model, which domain geometries correspond to sp, sp² and sp³? | sp: linear; sp²: trigonal planar; sp³: tetrahedral electron-domain geometry. | | | | 28 | For comparable ionic crystal structures, what increases lattice-energy magnitude? | Larger ionic charge magnitudes and smaller ion separations. Formation releases energy; separating the solid into gaseous ions requires energy. | | | | 29 | What mainly binds an ionic crystal together? | Electrostatic attraction between positive cations and negative anions throughout the lattice. | | | | 30 | What molecular shape does VSEPR predict for SF₄? | Seesaw. Five electron domains include four bonds and one lone pair; the lone pair occupies an equatorial site of the trigonal-bipyramidal domain arrangement. | | | | 31 | How do atomic number Z and mass number A differ? | Z counts protons and identifies the element. A counts protons plus neutrons in a nucleus. | | | | 32 | Which electrons mainly participate in ordinary chemical bonding? | Valence electrons; core electrons usually do not participate directly. Main-group valence electrons occupy the outermost shell; transition metals can also use d electrons. | | | --- Study this deck interactively with FSRS-6 spaced repetition, audio review, and multiple-choice mode at [Flashcards World](https://flashcards.world/flashcards/sets/fa6cff7c-4727-423a-a99e-e8c2592eac6b/).