Sample Plan :
Formation of Hydrogen, Oxygen and Nitrogen Molecules
Overview :
The
presentation on Alice World is to make students of Class IX to understand
formation of covalent bonds involving single, double and triple bonds.
Curricular Topic:
Covalent Bond
Author : Mrs.K. Ameeta , KVS ZIET, Chandigarh
Author : Mrs.K. Ameeta , KVS ZIET, Chandigarh
Learning Objectives:
To enable
the students to:
·
identify the
instability of hydrogen ,oxygen and nitrogen atoms .
·
understand the
possibility of gaining stability by sharing of electrons.
·
know about covalent
bonds.
Activity Duration:
15 min –
demonstration for each kind of covalent bond
Materials Required:
LCD
Projection system
Alice 3
software
Formation
of Covalent Bond
A covalent
bond is formed when the atoms of same or different elements combine by mutual
sharing of electrons. Covalent compounds are formed only by the interactions of
non-metal atoms. The number of atoms which make up covalent molecules is
determined by the number of electrons in outer levels and the Octet Rule.
HYDROGEN: Forms
single Covalent Bond
The simplest
covalent molecule is the diatomic hydrogen molecule.
The
"octet" for hydrogen is only 2 electrons since the nearest noble gas
is He. The diatomic molecule is formed because individual hydrogen atoms
containing only a single electron are unstable. The covalent bond holds the two
atoms together because the pair of electrons is attracted to both nuclei.
OXYGEN: Forms double
Covalent Bond
Oxygen has six
valence electrons , hence short of two
electrons to attain the stability of nearest noble gas Ne.
To attain
stability double covalent bond is formed by sharing of four electrons between
two oxygen atoms.
NITROGEN: Forms
triple Covalent Bond
Nitrogen has five
valence electrons , hence short of three electrons to attain the stability of
nearest noble gas Ne.
To attain
stability triple covalent bond is formed by sharing of four electrons between
two oxygen atoms.
Conditions
necessary for the formation of covalent bonds:
·
A bond formed by mutual sharing of electrons
·
Formed between two or more non-metals – difference in electro
negativity should not be high.
·
A single bond represents 2 electrons
·
They satisfy the octet rule by sharing of electrons
·
These molecules have a definite shape
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