Tuesday, November 10, 2009
Monday, November 9, 2009
Friday, November 6, 2009
Structure of Atom
1 Table 1 shows the incomplete information about 3 atoms; X, Y and Z.
| Atom | Proton number | Number of neutron | Number of electron |
| X | | 8 | 6 |
| Y | 6 | 6 | |
| Z | 17 | | 17 |
Table 1
(a) State the name of subatomic particles that are found in nucleus of an atom.
…………………………………………………………………………………………… [1 mark]
(b) (i) What is the term of the total number of protons and neutrons in an atom?
…………………………………………………………………………………… [1 mark]
(ii) The total number of protons and neutrons for atom Z is 35.
What is the number of neutron in atom Z?
…………………………………………………………………………………… [1 mark]
(iii) Write the symbol for atom Z in the form of A X.
Z
…………………………………………………………………………………… [1 mark]
(iv) Draw the atomic structure of atom Z.
[1 mark]
(c) Atom X and atom Y are isotopes of an element.
(i) What is the proton number of atom X?
…………………………………………………………………………………… [1 mark]
(ii) Write the electron arrangement of atom Y.
…………………………………………………………………………………… [1 mark]
(iii) What is valence electron of atom X?
…………………………………………………………………………………… [1 mark]
(iv) Why atom X and atom Y has same chemical properties?
…………………………………………………………………………………… [1 mark]
(v) State one use of the isotope X in archaeology field.
…………………………………………………………………………………… [1 mark]
2 Diagram 2 shows the chemical symbols which represent three elements X, Y and Z
The letters used are not the actual symbols of the elements.
| 9 X 4 | | 32 Y 15 | | 31 Z 15 |
Diagram 2
(a) (i) What is meant by proton number?
…………………………………………………………………………………… [1 mark]
(ii) State the proton number for atom X
……………………………………………………………………………………… [1 mark]
(b) What is represented by the number 32 for the element Y?
……….…………………………………………………………………………………… [1 mark]
(c) (i) Atom Y and Z are isotopes. State the difference between the two atoms.
..……………………………………………………………………………………… [1 mark]
(ii) State one use of isotopes in daily life.
……………….……………………………………………………………………… [1 mark]
(d) (i) Write the electron arrangement of atom Y.
……………………………………………………………………………………… [1 mark]
(ii) Determine the number of valence electron for atom Y.
……………………………………………………………………………………… [1 mark]
(ii) Draw the electron arrangement for atom Z.
[2 marks]
3 Diagram 3.1 shows the arrangement of particles of substance X at different temperatures.
 |
(a) What is the physical state of substance X at
(i) 60 oC : .........................................................................
(ii) 90 oC : ......................................................................... [2 marks]
(b) State the movement of particles of substance X at 60 oC.
....……………………………………………………………………………………… [1 mark]
(c) Graph 3.2 shows the graph of temperature against time when substance X is heated from 60 oC to 90 oC. (i) What is meant by melting point?
……………………………………………………………………………………………..
……………………………………………………………………………………[1 mark]
(ii) Based on Graph 3.2, state the melting point of substance X.
…………………………………………………………………………………… [1 mark]
(iii) Explain why the temperature remains constant from t1 to t2.
...................................................................................................................................
................................................................................................................................[2 marks]
(d) (i) Substance X cannot conduct electricity in any state.
State the type of particles of substance X.
..................................................................................................................................[1 mark]
(ii) Table 3.3 shows two substances.
| Magnesium oxide | |
| Carbon dioxide | |
|
Which substance has the same type of particles as substance X?
Tick (√ ) the correct answer.
[1 mark]
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