Science - Teachers Sri Lanka

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² An atom reach the maximum nobel gas configuration by
forming one or more bonds.
² Molecules are formed by atoms joining together by
chemical bonds.
² A molecules consists of two or more atoms which may be
homogeneous or heterogeneous.
² When chemical bonds form between heterogeneous atoms
compounds are formed.
² It is possible to develop the chemical equation of a com
pound by indicating the different number of atoms in a
compound molecule using the symbols of elements.
(15 mts)
Step 1.3.2 : ² Divide the class into two groups.
² Provide the groups with instruction for exploration the
article,demy papers and pastel.
² Assign the tasks and engage the groups in exploration.
² Prepare them to present their findings to the whole class.
(60 mts)
Step 1.1.3 (² Get each group to present their findings to the class.
² Give the first opportunity to the respective group to
elaborate on the presentation.
² Get the other groups to propose constructive suggestions,
² Elaborate highlighting the following points.
That,
² Atoms of elements by releasing electrons become positive
ions,and by receiving electrons become negative ions.
² The positive ions are named cations and the negative ions as
anions.
² There are ions which are formed from a single atom or from
a number of atoms.
² Oppositely charged ions are attracted together and thereby
forming ionic bonds,
² When ions get together to form a compound,the arrange
ment of ions in space is called the ionic lattice.