感謝元祖芒果對我昨天post 的留言。我也很想和你吃cereal，但沒有辦法，兼職芒果不能做數學白癡啊，雖然現在都快要變了。 話説化學老師決定星期三到五選一天，但要知道的是，星期三測驗和星期五，可是天淵之別啊。那也沒有關係，兼職芒果還是要溫習的，今天和大家說一下比較入門的 Giant metallic structure. 172Please respect copyright.ＰＥＮＡＮＡ2wwLmU5U1W
All metals have a giant metallic structure, this is a regular three-dimensional arrangement of metal ions in a 'sea' of delocalized electrons.
The strong electrostatic attraction between positive metal ions (cations) and negative delocalised electrons makes up the metallic bond. Metallic bond is non-directional, because metal ions and delocalised electron attract each other in all directions.172Please respect copyright.ＰＥＮＡＮＡTajFDJivFx
The physical properties of metals can be explained by its structure and bonding.
1. high melting point and boiling point 172Please respect copyright.ＰＥＮＡＮＡm2e7MXKdc3
The metal ions and delocalised electrons in metal are held by strong metallic bond. Much energy is needed to break the metallic bond.
2. malleable and ductile 172Please respect copyright.ＰＥＮＡＮＡLyjJWcNZYr
This is because when an external force is applied to metal, the layers of metals ions in the metal can slide over each other without breaking the metallic bond with delocalised electrons. 172Please respect copyright.ＰＥＮＡＮＡ8IIbaH0QPY
3. conductor of electricity 172Please respect copyright.ＰＥＮＡＮＡIZqO4GLIt9
quick definition of 'conductor' :172Please respect copyright.ＰＥＮＡＮＡhpDqiXw1ah
a conductor of electricity means the substance can conduct electricity in solid and liquid/ molten state and they must use delocalised electrons to conduct electricity. They are also not chemically changed during the conducting of electricity. Hence, it can be deduced that all metals and graphite are conductors of electricity.172Please respect copyright.ＰＥＮＡＮＡ3kEyEiuSLQ
It is because delocalised electrons are presented in metals.
4. good conductor of heat 172Please respect copyright.ＰＥＮＡＮＡoQK8lwBMze
Because when the metal is being heated, the delocalised electrons will gain more kinetic energy. They move and vibrate faster and collide with the neighbouring slow delocalised electrons. Heat is therefore transferred.
5. high density (except: Li, Na, K ) 172Please respect copyright.ＰＥＮＡＮＡjy9gONUcHO
( note: Li, Na, K can float on water, hence they have low density )
The metal ions in the metal are closely packed with a regular arrangement by strong metallic bonds with delocalised electron. 172Please respect copyright.ＰＥＮＡＮＡkP9Uy2REB1
172Please respect copyright.ＰＥＮＡＮＡUGRYkdol4D
and then Add to home screen.