氫為什麼歸在7A族

I don't think hydrongen should be placed in group 1A on many periodic charts,
since it is not an alkai metal.

Hydrogen is included with group 7A since氫只有1粒電子，當2個氫原子形成共價鍵時，
它們會互相提供1粒電子共用，形成簡單分子。

H一H(單鍵)

Halogen do so.都是形成單鍵，而一個分子都是由2個原子組成。

Cl一Cl

因兩者有此相似性，so on other periodic charts,hydrogen is included with group 7A even though it is not a halogen.

I think hydrogen should not be placed in any group,although hydrogen have one electron
but hydrogen is a gas when group 1 element are metal

Hydrogen放係Group 1A同7A都有原因 :

1A既原因 : 所有Group 1A既element都有1粒electron係outermost S-shell，即係最外圍既s-orbital度得1粒electron‧所以，縱使Hydrogen唔係alkali metal，但由於佢有只得Group1A有既特質而其他Group無的，佢都可以放係Group 1A

7A既原因 : 上面既樓主講得都好詳細的‧由於Hydrogen果1粒electron既普遍特性都係同自己 form covalent bond( H--H )而唔係ionic(雖然係有Hydride ion H-,但唔common)，而Group 7A都係例如 Cl -- Cl及 I -- I，而放係7A唔係6/5A既原因就係當同自己form covalent bond既時候，佢地都只係share 1粒electron to each other而唔係2/3甚至4粒‧

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