F.3 CHEMISTRY MC

A , As u would know that if it can form an anion, it is more likely to be an element that it's outermost shell electron more than 4. Base on our knowlage, we know that they are always non-metal and non-metat won't conduct eletricity in any state. Therefore, we know that it is incorrect.

B, As anion is geting electrons from others, if it's electronic arrangement is 2,8,8, we know that the element itself hv electron less than this number. Thus, we know that it is incorrect.

C, From my ecplaination in A & B, we know that the element have an electronic arrangement of less than 2,8,8 and it's outermost shell electron more than 4. Base on our knowlage we know that there is no solid element at rm temp. and pressure in this range. We know that this answer is in correct too.

D, We know that Ca will form cation. If element X can form anion, it would react wif some element which can form cation. So, it is correct.

i dun understand

i think all ABCD are not correct...
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2006-12-28 09:24:39 補充：
i know la~ans is CX forms an ion charged 2-,atomic no. of X is 16it is sulphur and is a solid at room temp. and pressure

A. X can conduct electricity in its molten state

(X can be Phosphorus, Sulphur or Chlorine. they all can conduct electricity in its molten state)

B X is in Period 4 of the periodic table

(It must wrong. X can be Phosphorus, Sulphur or Chlorine, they are all in Period 3.)

C X is a solid at room temp. and pressure

(X can be Phosphorus, Sulphur or Chlorine. However, Chlorine is not a solid at room temp. and pressure.)

D X can react with calcium to form a compound with the formula CaX2.

(We can't don't if it is Sulphur or not.)