question marking guidance mark comments mark scheme a level chemistry chem june a b general increase greater nuclear charge more protons same shielding electrons added to same shell stronger attraction from nucleus for outer electron s aluminium al lower than mg outer electron in p orbital sub shell level p higher in energy or sulfur s lower than p outer electrons in p orbital begin to pair repel c sulfur s large jump after th or between th and th if not increase then ce allow similar allow electron in outer shell ce if not al or s if p or p orbital lose m and m allow more shielded or weaker nuclear attraction m is dependent on m if p or p orbital lose m and m allow electrons in p m is dependent on m ce if not s do not allow m if atom ion is removed silicon giant covalent structure macromolecule covalent bonds many strong covalent bonds or covalent bonds need lots of energy to break d mark scheme a level chemistry chem june ce if not si giant covalent scores m and m ce for m m if molecules metallic ionic imfs mentioned