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Chemistry Form 4 • MODULE

EXERCISE / LATIHAN
1 The diagram below shows the electron arrangement for atoms P and Q.
Rajah di bawah menunjukkan susunan elektron bagi atom P dan Q.

P P Q
Q

(a) Elements P and Q are placed in the same group in Periodic Table. State the group.
Unsur P dan Q terletak dalam kumpulan yang sama dalam Jadual Berkala. Nyatakan kumpulan itu.
Group 1
(b) How is elements P and Q kept in the laboratory? Give reason for your answer.
Bagaimanakah unsur P dan Q disimpan di dalam makmal? Berikan sebab bagi jawapan anda.
In paraffin oil. To prevent them from reacting with oxygen or water vapour in the atmosphere.
(c) (i) Write chemical equation for the reaction between elements P with water.
Tuliskan persamaan kimia untuk tindak balas antara unsur P dengan air.
2P + 2H O 2POH + H
2 2
(ii) What is the expected change of colour when a few drops of phenolphthalein are added into the aqueous
solution of the product? Explain your answer.
Apakah perubahan warna yang dijangkakan apabila beberapa titik fenolftalein dititiskan ke dalam larutan akueus yang
terhasil? Terangkan jawapan anda.
Colourless to purple/ pink. The solution formed is alkaline.
(iii) Between element P and element Q, which is more reactive in the reaction with water?
Antara unsur P dan Q, yang manakah lebih reaktif apabila bertindak balas dengan air?
Element Q is more reactive than P.
(iv) Explain your answer in (c)(iii) / Terangkan jawapan anda dalam (c)(iii).
The size of atom Q is larger than atom P.
The valence electron of atom Q is further away from the nucleus compared to atom P.
The attraction forces between proton in the nucleus to the valence electron of atom Q is weaker than atom P.

Atom Q is easier to release the valence electron compared to atom P.
(d) Name one element that has the same chemical properties as P and Q.
Namakan satu elemen yang mempunyai ciri-ciri kimia yang sama dengan P dan Q.
Potassium

2 The diagram below shows the information regarding elements W and X which are from the same group in the Periodic
Table.
Rajah di bawah menunjukkan maklumat mengenai unsur W dan X yang terletak di kumpulan yang sama dalam Jadual Berkala.
19 W 35 X
9 17
(a) (i) Write the electron arrangement of atom of elements W and X / Tuliskan susunan elektron bagi atom unsur W dan X.
Atom W / Atom W : 2.7 Atom X / Atom X : 2.8.7
(ii) State the position of elements W and X in the Periodic Table.
Nyatakan kedudukan unsur W dan X dalam Jadual Berkala.
Element W / Unsur W : Group 17, Period 2
Element X / Unsur X : Group 17, Period 3
(iii) Do elements W and X show the same chemical property? Explain your answer.
Adakah unsur W dan X menunjukkan sifat kimia yang serupa? Terangkan jawapan anda.
Elements W and X have the same chemical property. Atoms W and X have the same number of valence
electrons.
(b) State the type of particles of substances W and X / Nyatakan jenis zarah yang terdapat pada W dan X.
Molecule

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