SPM Chemistry (KBSM) Paper 1

02 Structure of Atom
2.1 Matter
2 Lessons
2.1.1 The Particle Theory of Matter
2.1.2 Changes in the State of Matter
2.2 The Atomic Structure
2 Lessons
2.2.1 History of Development
2.2.2 The Modern Atomic Model
2.3 Isotopes
1 Lesson
2.3.1 Isotopes
2.4 Arrangement of Electrons
1 Lesson
2.4.1 Electron Arrangement
2.5 Practices - Structure of Atom
03 Formular and Equations
03 Practices - Formulae and Equations
3 Exercises
3a Formulae and Equations I
3b Formulae and Equations II
3c Formulae and Equations III
04 Periodic Table
04 Practices - Periodic Table
3 Exercises
4a Periodic Table I
4b Periodic Table II
4c Periodic Table III
05 Chemical Bond
05 Practices - Chemical Bond
3 Exercises
5a Chemical Bond I
5b Chemical Bond II
5c Chemical Bond III
06 Electrochemistry
06 Practices - Electrochemistry
3 Exercises
6a Electrochemistry I
6b Electrochemistry II
6c Electrochemistry III
07 Acids and Bases
07 Practices - Acids and Bases
4 Exercises
7a Acids and Bases I
7b Acids and Bases II
7c Acids and Bases III
7d Acids and Bases IV
08 Salts
08 Practices - Salts
3 Exercises
8a Salts I
8b Salts II
8c Salts III
09 Manufactured Substances in Industry
09 Practices - Manufactured Substances in Industry
3 Exercises
9a Manufactured Substances in Industry I
9b Manufactured Substances in Industry II
9c Manufactured Substances in Industry III
10 Rate of Reaction
10 Practices - Rate of Reaction
3 Exercises
10a Rate of Reaction I
10b Rate of Reaction II
10c Rate of Reaction III
11 Carbon Compounds
11 Practices - Carbon Compounds
4 Exercises
11a Carbon Compounds I
11b Carbon Compounds II
11c Carbon Compounds III
11d Carbon Compounds IV
12 Oxidation and Reduction
12 Practices - Oxidation and Reduction
4 Exercises
12a Oxidation and Reduction I
12b Oxidation and Reduction II
12c Oxidation and Reduction III
12d Oxidation and Reduction IV
13 Thermochemistry
13 Practices - Thermochemistry
2 Exercises
13a Thermochemistry I
13b Thermochemistry II
14 Chemicals for Consumers
14 Practices - Chemicals for Consumers
2 Exercises
14a Chemical for Consumers I
14a Chemical for Consumers II
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2.2.2 The Modern Atomic Model

SPM Chemistry (KBSM) Paper 1 2.2 The Atomic Structure 2.2.2 The Modern Atomic Model
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The Modern Atomic Model

According to the modern atomic model,
  1. The central nucleus consists of protons and neutrons. It containing almost all the mass of the atom.
  2. the nucleus of an atom is very small compared to the size of the atom
  3. the electrons are orbiting outside the nucleus in the electron shells
  4. the electrons are moving in electron shells at a very high speed and we cannot determine the position of the electrons at a particular time

The Subatomic Particles of an Atom​

  1. Atoms are made up of tiny particles called subatomic particles.
  2. An atom contains three types of subatomic particles:
    1. proton,
    2. neutron and
    3. electron,
  3. The proton and neutron form the nucleus at the centre of an atom. They are also called the nucleon of an atom.
  4. The electron moves around the nucleus at a very high speed.
  5. The nucleus is positively charged because of the presence of protons, which are positively charged. The neutrons are neutral.
  6. The symbols, charge and relative masses of proton, neutron and electron are as below.
ParticleSymbolRelative chargeRelative mass
Proton
p
+1
1
Neutron
n
0
1
Electron
e
-1
1/1840

The Charge of Particles

  1. A neutral atom contains the same number of electrons as the protons.
  2. The positive and negative charges of the protons and electrons respectively neutralise each other, for example, (+4) + (-4) = 0
  3. If the number of protons is greater than the number of electrons, the particle is positively charged.
  4. If the number of protons is greater than the number of electrons, the particle is positively charged.

Example:

Number of protonsNumber of electrons
Charge
3
3
0
5
2
+3
9
10
-1
11
10
+3
16
18
-2
17
18
-1
20
18
+3

Proton Number and Nucleon Number

  1. Proton number = the number of protons
  2. Nucleon number = Number of protons + Number of neutrons

Proton Number

  1. The proton number (Z) represent the number of protons found in the nucleus of an atom.
  2. Proton number = the number of protons
  3. The proton number is also known as the atomic number.
  4. In an atom of neutral charge, the number of electrons also equals the atomic number.
  5. Hence, the proton number of an atom can also represent the number of electrons.

Nucleon Number

  1. The nucleon number (A), also called atomic mass number or mass number, is the number of protons plus the number of neutrons in an atomic nucleus. (Nucleon number = Number of protons + Number of neutrons)
  2. The nucleon number of an atom is about the same as the mass of the atom because the mass of an electron is very small and can be ignored.
Atom
Proton Number
Nucleon Number
Amount of Proton
Amount of Neutron
Helium
2
4
2
2
Oxygen
8
16
8
8
Sodium
11
23
11
12
Chlorine
17
35
17
18
[Notes: In ion, the amount of protons IS NOT equal to the amount of electrons]
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