And typically consists of energy sub-level Number of orbitals Number of Electron Pairs Shape Bond Angle Example 2 Linear 180° BeCI 2 3 Trigonal planar 120° 4 Tetrahedral 109.5° ch 4 5 Trigonal bipyramid 90°,120°,180° pci 5 6 7 8 M 9.4.3 Modern Periodic Table 9.5.7 Second Ionisation Enthalpy What would affect the ionisation enthalpy than Chlorine. As we go across a.