f3/ f4. Chem

a) They change from metal, metalloid and finally non-metal.
三個字 "metal", "metalloid" and "non-metal"都要講。
冇咗metalloid可以扣你分。

Or,

They change from solid to gas. 呢個可以唔寫liquid，因為中三、四課程
只要求睇頭3個period.

001的朋友:

the melting point 同 boiling point 唔會decrease across the period
Go and check your textbook CAREFULLY!
呢個CONCEPT係錯嘅

發問者：唔好用melting point 同boiling point 。個個period都唔同

e.g. in period 2, the melting point 由Li to C 上升and then 由
N to Ne 下降
e.g.in period 3 , the melting point 由 Na to Si都係上升. From Si to P, melting
point 下降。 From P to S, melting point 上升。 From S to Ar, melting下降

結論：唔好用melting point 同boiling point答。可能你而家F.4未學到。F.5會詳細解釋，唔駛擔心。

bi) They both react with water to form strong alkaline solution
Or, When they are burnt, they react with oxygen to form oxides.
Or, They react with acid explosively to form salt and hydrogen
是但一個

bii) They both react with water to form strong acid solution.
Or, they react with alkane under UV to form haloalkane (中四下學期會教)
是但一個

c) Potassium and Fluorine (since reactivity of group 1 and group 7 elements
increase down and decrease down the group respectively)

001&發問者:逢人哋問你邊種metal or non-metal或者某個物質的名唔可以寫
symbols,一定要寫全寫，否則會1分都冇。

d) x=18 (佢喺transition metal後面，所以啲e-會入滿第3個Shell
y=8 [Krypton 係 group 8 (or group 0)]

for ei,
Casesium dissolves and burns very vigorously. Colourless bubbles are given off.

**人哋問你observation，唔係問你整個reaction會有咩products.所以只要寫你睇到嘅嘢就夠

001:唔可以就咁寫 release gas，因為唔夠完整，會冇分。仲有，佢唁係就咁
burn，係burn very vigorously，你咁寫可以唔俾分。

eii) It can be stored under paraffin oil

2013-08-13 22:04:21 補充：
對。謝謝001及0022位高手

b ii)

HF並唔係strong acid吧

將strong acid solution改成acidic solution比較穩妥

a)
"Metal", "metalloid" (or "semi-metal") and "non-metal" are NOT physical properties.

One possible answer is :
The ATOMIC RADIUS is gradually decreasing when going across a period.