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.

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.

How does Hund's rule fill equal-energy orbitals within a subshell?

Place one electron in each orbital with parallel spins before pairing electrons.

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.

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.

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.

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.

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.

What makes two atoms isotopes of the same element?

They have the same number of protons but different numbers of neutrons.

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.

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.

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.

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.

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.

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.

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.

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.

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.

How many σ and π bonds form the carbon–carbon triple bond in ethyne?

One σ bond and two mutually perpendicular π bonds.

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.

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).

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.

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.

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.

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.

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.

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.

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.

What mainly binds an ionic crystal together?

Electrostatic attraction between positive cations and negative anions throughout the lattice.

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.

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.

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.

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.

Level: basic
Languages: en → en
Cards: 32
Markdown: Atomic Structure, Periodic Trends & Chemical Bonding (.md)

Flashcards (32)

#	Front (Term / Question)	Back (Definition / Answer)
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.