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01 Atomic structure
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2. Atom

3. Two major parts of atom? 1.Nucleus- contains protons and neutrons
2. Extra nuclear part- contains electrons

4. Draw of the atom.

5. Structure of Atom
Nucleus
Electron
Shell or Orbit

6. Description of the Nucleus
The nucleus is the central part of an atom.
It is composed of protons and neutrons.
The nucleus contains most of an atom's mass.
It was discovered by Ernest Rutherford in 1911.

7. Description of Proton Proton is positively charged particle.
It is found in the atomic nucleus.
Protons were discovered by Ernest Rutherford.

8. Describe Neutron Neutron is uncharged particle.
It is found in the atomic nucleus.
Neutron was discovered by James Chadwick in 1932.

9. Describe Electron Electron is a negatively charged particle.
Electron revolves around the nucleus in a definite circular path.
Electrons was discovered by J. J. Thomson in 1897.
Electrons determine properties of the atom.
Chemical reactions involve sharing or exchanging electrons.

10. The structure of the atom
ELECTRON – negative,
Nigligible mass o.ooo555amu
PROTON – positive,
Mass amu
NEUTRON – neutral,
mass amu

11. The Hydrogen Atom Proton Electron
Hydrogen has one proton, one electron and NO neutrons

12. The Helium Atom Proton Electron Neutron
Helium has two electrons, two protons and two neutrons

13. The Lithium Atom
Electrons
Protons
Neutrons

14. The Beryllium Atom Electrons Protons Neutrons
Beryllium has four electrons, four protons and five neutrons.

15. The Boron Atom Electrons Protons Neutrons
Boron has five electrons, five protons and six neutrons.

16. The Carbon Atom Electrons Protons Neutrons
Carbon has six electrons, six protons and six neutrons.

17. The Nitrogen Atom Electrons Protons Neutrons
Nitrogen has seven electrons, seven protons and seven neutrons.

18. The Oxygen Atom Electrons Protons Neutrons
Oxygen has eight electrons, eight protons and eight neutrons.

19. The Fluorine Atom Electrons Protons Neutrons
Fluorine has nine electrons, nine protons and ten neutrons.

20. The Neon Atom Electrons Protons Neutrons
Neon has ten electrons, ten protons and ten neutrons.

21. The Sodium Atom Electrons Protons Neutrons
Sodium has eleven electrons, eleven protons and twelve neutrons.

22. Atomic number (Z)
Atomic number (Z): The number of protons in the nucleus which exactly balances the number of electrons in orbits.
Atomic number(Z) = No.of protons
= No.of electrons
Atomic number = P = e-

23. Atomic Mass number (A)
Atomic Mass number (A): The total number of protons and neutrons present in the nucleus of an atom.
Atomic Mass number (A) = No.of protons
+ No.of neutrons
Atomic Mass number (A) = P + N

24. Example 4 He 2 MASS NUMBER = number of protons + number of neutrons
SYMBOL
PROTON NUMBER = number of protons (obviously)

25. How many protons, neutrons and electrons?1 11 16 H B O 1 5 8 23 35
238 Na Cl U 11 17 92

26. Electronic structure of PotassiumK 19 39
Potassium has 19 electrons. These are arranged in shells…
The inner shell has __ electrons
The next shell has __ electrons
The next shell has the remaining __ electron
Electron structure
= 2,8,8,1

27. How do shells fill?
The first electron shell can only hold a maximum of two electrons.
The second electron shell can hold a maximum of eight electrons.
The third electron shell can also hold a maximum of eight electrons.
The fourth electron shell can also hold eight electrons.

28. The First Twenty Elements
Hydrogen 1,0,0,0
Helium ,0,0,0
Lithium ,1,0,0
Beryllium 2,2,0,0
Boron ,3,0,0
Carbon ,4,0,0
Nitrogen ,5,0,0

29. First 20 Elements continued
Oxygen ,6,0,0
Fluorine ,7,0,0
Neon ,8,0,0
Sodium ,8,1,0
Magnesium 2,8,2,0
Aluminium 2,8,3,0
Silicon ,8,4,0

30. First 20 Elements continued
Phosphorus ,8,5,0
Sulphur ,8,6,0
Chlorine ,8,7,0
Argon ,8,8,0
Potassium ,8,8,1
Calcium ,8,8,2

31. Describe Isotopes Atoms that have the same number of
protons but different numbers of
neutrons

32. Example of Isotopes of Hydrogen

34. The Nobel gases
The Nobel gases have full outer shells and they are found in group 0 of the periodic table. Helium, Neon, Argon, Krypton, Xenon and Radon.

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The Halogens
Fluorine, Chlorine, Bromine and Iodine are the Halogens and they all have seven electrons in their outer shell. This is why they are found in group 7 of the periodic table.
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