Describe relative atomic mass, \( A_r \), as the average mass of the isotopes of an element compared to 1/12th of the mass of an atom of \( ^{12}C \)
Describe how the properties of fractions obtained from petroleum change from the bottom to the top of the fractionating column, limited to: (a) decreasing chain length (b) higher volatility (c) lower boiling points (d) lower viscosity
Describe the formation of covalent bonds in simple molecules, including \( H_2 \), \( Cl_2 \), \( H_2O \), \( CH_4 \), \( NH_3 \), \( HCl \), \( CH_3OH \), \( C_2H_4 \), \( O_2 \), \( CO_2 \) and \( N_2 \). Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules