All elements are made of atoms.
Atoms are made of subatomic particles.
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Look at the diagram of an atom.
Which particles are present in the charge cloud?
Which two particles make up the nucleus?
............................................. and .............................................
Most of the mass of an atom is in the nucleus.
Explain why.
Look at these two atoms of chlorine.
What is the relationship between these two atoms of chlorine?
Explain your answer.
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4 marksLook at Table 24.1.
It shows information about some atoms and ions.
| Particle | Atomic number | Mass number | Number of protons | Number of neutrons | Number of electrons | Electronic structure |
| A | 11 | 23 | 11 | .............. | 11 | 2.8.1 |
| B | 23 | 19 | 9 | 10 | 9 | .............. |
| C | .............. | 37 | 17 | .............. | 17 | 2.8.7 |
| D | 13 | 27 | .............. | .............. | 10 | 2.8 |
Table 24.1
Complete the missing information in Table 24.1.
Particle A is a metal atom, particle D is an ion.
Explain why.
Element C has the electronic structure 2.8.7.
What does this electronic structure tell you about the position of element C in the periodic table?
Explain your answer
Complete the table below to give information about protons, neutrons and electrons.
| Charge | Mass in atomic mass units |
|
| proton | ......................... | 1 |
| neutron | ......................... | ......................... |
| electron | negative | ......................... |
Rutherford was a scientist who helped to develop the atomic model.
State how Rutherford’s work contributed to the development of the atomic model.
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Look at the information about two atoms of chlorine.
The atomic number of chlorine is 17.
What is meant by atomic number?
These two atoms of chlorine are isotopes.
Explain why these two atoms of chlorine are isotopes.
4 marksLook at the information about other atoms and ions.
| Atom or ion | Atomic number |
Mass number |
Number of protons |
Number of neutrons |
Number of electrons |
Electronic structure |
| S | 16 | 32 | .............. | 16 | 16 | .............. |
| B | 5 | 11 | 5 | .............. | .............. | 2.3 |
| F− | 9 | 19 | ............. | .............. | 10 | 2.8 |
| Li+ | 3 | 7 | 3 | 4 | .............. | .............. |
Complete the table.
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