Chemical Bonding structured questions · GCE A-Level H1 Chemistry

Learning objectives

• show understanding that all chemical bonds are electrostatic in nature and describe: — ionic bond as the electrostatic attraction between oppositely charged ions
• show understanding that all chemical bonds are electrostatic in nature and describe: — covalent bond as the electrostatic attraction between a shared pair of electrons and positively charged nuclei
• show understanding that all chemical bonds are electrostatic in nature and describe: — metallic bond as the electrostatic attraction between a lattice of positive ions and delocalised electrons
• describe, including the use of ‘dot-and-cross’ diagrams, — ionic bonding as in sodium chloride and magnesium oxide
• describe, including the use of ‘dot-and-cross’ diagrams, — covalent bonding as in hydrogen; oxygen; nitrogen; chlorine; hydrogen chloride; carbon dioxide; methane; ethene
• describe, including the use of ‘dot-and-cross’ diagrams, — co-ordinate (dative covalent) bonding, as in formation of the ammonium ion and in the Al2Cl6 molecule
• describe covalent bonding in terms of orbital overlap (limited to s and p orbitals only), giving σ and π bonds (see also Section 9)
• explain the shapes of, and bond angles in, molecules such as BF3 (trigonal planar); CO2 (linear); CH4 (tetrahedral); NH3 (trigonal pyramidal); H2O (bent); SF6 (octahedral) by using the Valence Shell Electron Pair Repulsion theory
• predict the shapes of, and bond angles in, molecules analogous to those specified in (d)
• explain and deduce bond polarity using the concept of electronegativity [quantitative treatment of electronegativity is not required]
• deduce the polarity of a molecule using bond polarity and its molecular shape (analogous to those specified in (d))
• describe the following forces of attraction (electrostatic in nature): — intermolecular forces, based on permanent and induced dipoles, as in liquid and gaseous CHCl3, Br2 and the noble gases
• describe the following forces of attraction (electrostatic in nature): — hydrogen bonding, using ammonia and water as examples of molecules containing –NH and –OH groups
• outline the importance of intermolecular forces to the liquefaction of gases when subjected to high pressure and/or low temperature
• outline the importance of hydrogen bonding to the physical properties of substances, including ice and water
• explain the terms bond energy and bond length for covalent bonds
• compare the reactivities of covalent bonds in terms of bond energy, bond length and bond polarity
• describe, in simple terms, the lattice structure of a crystalline solid which is: — ionic, as in sodium chloride and magnesium oxide
• describe, in simple terms, the lattice structure of a crystalline solid which is: — simple molecular, as in iodine
• describe, in simple terms, the lattice structure of a crystalline solid which is: — giant molecular, as in graphite and diamond
• describe, in simple terms, the lattice structure of a crystalline solid which is: — hydrogen-bonded, as in ice
• describe, in simple terms, the lattice structure of a crystalline solid which is: — metallic, as in copper [the concept of the ‘unit cell’ is not required]
• describe, interpret and/or predict the effect of different types of structure and bonding on the physical properties of substances
• suggest the type of structure and bonding present in a substance from given information