5. Which ONE of the following substances is LEAST ionic?
a)NaClb)KClc)CuCl2d)SbCl4 6. Calculate the difference in electronegativity (ΔEN) for the bonds that would form between the groups of atoms listed below. State whether the bond would be ionic, polar covalent or non- polar covalent. a) N and Cl ; molecule: NCl 3 – ΔEN= 3-2.1= 0.9 (weak polar covalent) b) B and Br ; molecule: BBr - ΔEN= 2.8-2= 0.8 (weak polar covalent) c) B and F ; molecule: BF 3 - ΔEN= 4-2= 2 (strong polar covalent) d) Al and O ; molecule: Al 2 O 3 - ΔEN= 3.5-1.5=2 (strong polar covalent) e) N and F ; molecule: molecule:NF 3 - ΔEN= 4-3= 1 (weak polar covalent) 7. Explain why HBr is a polar molecule, but H2and Br2are not.In HBr, a dipole can be formed because bromine has greater electronegativity, this means that electrons in this covalent bond will tend to stay towards bromine. However H2 and Br2 are compounds with no polarity because dipoles can't form. The elements in each compound are the same so have the same attraction to electrons when bonded. 8. Write the chemical formula you would expect for a combination of each of the following. Use a check mark to identify each combination as ionic or covalent (polar or non-polar) or whether no bond is formed. Atoms Formula no bond ionic polar covalent non-polar covalent F and Na NaF X C and F CF X F and F F2 X Ne and Ne Ne X Se and F SeF4 X
9. Predict what type of solid will be formed in each of the following: