F.4 [email protected]頭20隻elements....!?
USE 頭20隻 elements .
a . Name TWO elements which are obtained from fractional distillation of liquid air .
b . Why does argon consist of individual atoms instead of molecules of two or more atoma?
c . Carbon combines with element X to form a covalent compound with the formula CX2.
i.) To which group does X belong?
ii.) Draw an electron diagram for the compound, showing electrons in the outermost shells
d . Element Y forms a nitrate which has the formula Y(NO3)2 .
i.) To which group does Y belong ?
ii.) Predict the formula for the oxide of Y .
2 the following table gives some information about W , X , Y and Z which represent particles of some
elements . These particles are either atoms or ions .
Particle Mass NO. Atomic NO. protons electrons neutrons
W 14 7 7
X 9 9 10
Y 9 10 10
Z 10 19 20
a . W exisits as diatomic molecules . Draw an electron diagram for itsmolecule , showing electrons in
the outermost shells only.
i.) What is the relationship between X and Y ?
ii.) Suggest a chemical reaction in ehich X can change into Y .
c . X can form a compound whit Z .
i.) Draw an electron diagram for the compound .
ii.) Calculate the formula mass of the compound .