S2. Models of Bonding and Structure Flashcards
(35 cards)
What forms when metal atoms lose electrons?
They form positive ions called cations.
What forms when non-metal atoms gain electrons?
They form negative ions called anions.
How can you predict the charge of an ion?
From the electron configuration: atoms lose or gain electrons to achieve a full outer shell.
How do you deduce the formula and name of an ionic compound?
Combine the component ions to make a neutral compound. Include polyatomic ions like SO₄²⁻ or NH₄⁺
How do you convert between names and formulas of binary ionic compounds?
Use ion charges to write formulas and recognise compound names from formula structure.
Example: Mg²⁺ + Cl⁻ → MgCl₂ (magnesium chloride)
What are the physical properties of ionic compounds?
*Low volatility
*Conduct electricity when molten or aqueous
*Soluble in polar solvents
What is a covalent bond?
The electrostatic attraction between a shared pair of electrons and the positively charged nuclei.
What is the octet rule?
Atoms tend to gain a full outer shell of 8 electrons when bonding.
What are single, double, and triple bonds?
Bonds involving 1, 2, or 3 shared pairs of electrons, respectively.
What is a coordination bond (dative bond)?
A bond where both electrons in the pair come from one atom.
What is the VSEPR model used for?
To predict molecular shape based on repulsion between electron domains around a central atom.
What causes bond polarity?
The difference in electronegativities between two bonded atoms.
What determines molecular polarity?
Bond polarity and the shape of the molecule (geometry).
What are examples of covalent network structures?
Carbon (diamond, graphite, fullerenes, graphene) and silicon/silicon dioxide.
How does chromatography separate mixtures?
By using differences in intermolecular forces between substances and the mobile/stationary phases.
What types of intermolecular forces exist?
*London (dispersion)
*Dipole-dipole
*Hydrogen bonding
(Increasing strength: dispersion < dipole < hydrogen)
What is a Lewis structure and how do you draw it?
A diagram showing bonding and lone pairs in molecules and ions.
What is the relationship between number of bonds, bond length, and bond strength?
More bonds = shorter and stronger bond.
How do you predict molecular geometry from electron domains?
Use VSEPR theory; up to four electron domains (e.g. tetrahedral, trigonal pyramidal).
How do you determine polarity of a molecule?
Combine bond polarity and shape (geometry) to assess net dipole.
How do you identify intermolecular forces from molecular structure?
Check polarity, presence of hydrogen bonds, molecular mass and symmetry.
What are the physical properties of covalent substances?
*Volatility: often high
*Electrical conductivity: usually low
*Solubility: varies with polarity
What is the retardation factor (Rf) in chromatography?
Rf
distancetravelledbysubstance
/
distancetravelledbysolventfront
What is a metallic bond?
The electrostatic attraction between positive metal ions and delocalised electrons in a lattice.
