CHEMISTRY TOPIC 1

CHEMISTRY TOPIC 1

1. ATOMS AND THEIR STRUCTURE

   • Atoms are the basic units of matter and the defining structure of elements.
   • Atoms are made up of three particles: protons, neutrons and electrons. Protons and neutrons are heavier than electrons and reside in the center of the atom, which is called the nucleus.

2. SUB-ATOMIC PARTICLES

   • Composite subatomic particles (such as protons or atomic nuclei) are bound states of two or more elementary particles
   • For example, a proton is made of two up quarks and one down quark, while the atomic nucleus of helium-4 is composed of two protons and two neutrons

3. CHEMICAL EQUATIONS (subscript & superscript)

   • The atomic number is written as a subscript on the left of the element symbol.
   • the mass number is written as a coefficient on the left of the element symbol, and the ionic charge, if any, appears as a coefficient on the right side of the element symbol.

4. SEPARATING MIXTURES

   • The individual substances in a mixture can be separated using different methods, depending on the type of mixture.
   • These methods include filtration, evaporation, distillation and chromatography.

5. MODEL OF ATOMS

   • NUCLEAR
     • The Rutherford model is a model of the atom devised by Ernest Rutherford. Rutherford directed the famous Geiger–Marsden experiment in 1909 which suggested, upon Rutherford's 1911 analysis, that J. J. Thomson's plum pudding model of the atom was incorrect. ... This region would be known as the "nucleus" of the atom.
   • PLUM PUDDING
     • J. J. Thomson, who discovered the electron in 1897, proposed the plum pudding model of the atom in 1904 before the discovery of the atomic nucleus in order to include the electron in the atomic model. In Thomson's model, the atom is composed of electrons (which Thomson still called "corpuscles," though G. J.

6. ARRANGEMENT OF PERIODIC TABLE

   • GROUP 0
     • The group 0 elements are found on the right hand side of the periodic table.
     • They are called the noble gases because they are very unreactive.
   • GROUP 7
     • The group 7 elements are also known as the halogens.
     • They include fluorine, chlorine, bromine and iodine, which all have seven electrons in their outer shell.
     • . In a displacement reaction, a less reactive element is displaced by a more reactive element. The group 7 elements are placed in the vertical column second from right in the periodic table.
   • GROUP 1
     • The group 1 elements are found on the left hand side of the periodic table.
     • They are called the alkali metals because they form alkaline compounds.

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