chemisty--ionic bond 同covalent bond 問題 10點 help!!

ionic bond 有例外
NH4+ ge compound都係ionic bond
(特別例子)
咁metal 同metal係點? @@
metal同metal咪metallic bond
因為outermost shell of metallic atom is far away from the nulei and thus are loosely attractd.the metal atom may easy to lose electron from cation,the attractive force betwwwn cations and mobile ions are nn-directional .they present in metal only!!!