Port Said International Schools
Better Education for Future Generations Grade: 11
Science Department Unit 3 Revision
Name: ………………………………………. Date: ……………………………………………………
Write the scientific term for the following:
1.
A bond which is formed as a result of the overlap of two atomic orbitals side by side.
Egypt 2005
The pi bond
2.
A group of elements whose valence shell has less than half its capacity of electrons.
Egypt 2005
Metals
3.
The bond in hydrogen molecule is pure covalent, while the bond in hydrogen chloride is a polar covalent bond. Egypt 2005
Because in the hydrogen molecule the difference in electronegativity = 0 (similar elements), while in the hydrogen chloride molecule there is a difference in electronegativity between hydrogen and chlorine atoms (different atoms).
4.
A bond produced from the electron cloud of valence electrons which decreases the repulsive force between the positive metal ions in the crystal lattice. Egypt 2006
Metallic bond
5.
With the exception of hydrogen, lithium and beryllium the atoms of all elements tend to reach octet structure. Egypt 2006
The octet theory – The electronic theory of valence
6.
The bond which is formed as a result of the overlap of two atomic orbitals on one line (heat-to-head). Egypt 2009
The sigma bond
7.
Covalent bond between sp – sp orbitals. Egypt 2010
Sigma bond
Choose the correct answer:
1.
When ammonium ion is formed, ammonia molecule is linked with the proton to form (ionic – coordinate – covalent – metallic bond) bond. Egypt 2005
2.
The oxidation number of hydrogen in sodium hydride is (+1 – (-1) - +2 – (-2)).
Egypt 2005
3.
When sodium nitrate is heated (NO – NO
2
– N
2
O – O
2
) gas evolved. Egypt 2006
4.
The ionic bond is often formed between (different metals – metals and nonmetals
– nonmetals – metalloids). Egypt 2006
5.
The bonds in ammonium hydroxide molecules are (polar covalent – ionic – coordinate – all the previous ). Egypt 2007
6.
Ammonium chloride molecule NH
4
Cl contains (ionic – covalent – coordinate – all the previous ) bond(s). Egypt 2009
7.
The strongest hydrogen bonds are those between the molecules of ( HF – HBr – HCl
– HI).
Egypt 2010
8.
The type of hybridization in carbon atoms of the ethylene molecule is
(sp – sp 2 – sp 3 – sp 3 d 2 ). Egypt 2010
9.
Sp hybridized orbitals are characterized by (three orbitals – linear in shape – two orbitals – two orbitals and linear shape ). Egypt 2011 http://pisscience.wikispaces.com/

Port Said International Schools
Better Education for Future Generations Grade: 11
Science Department Unit 3 Revision
Give reasons for the following:
1.
The aluminum metal
13
Al is harder than sodium
11
Na. Egypt 2005
Because the metallic bond in aluminum is harder than the metallic bond in sodium due to the the existence of 1 electron in the outermost energy level of sodium and 3 electrons in the outermost energy level in aluminum
2.
The angle between two hybridized orbitals sp, sp in C
2
H
4
molecule = 180 ° . Egypt
2006
To reduce the repulsion force between the electrons inside the orbitals
3.
The boiling point of water is relatively high. Egypt 2007
Due to the existence of the hydrogen bond
4.
Ammonium hydroxide has three types of bond. Egypt 2010
Because of the followings:
The bond between nitrogen and hydrogen in the NH
3
molecule is covalent.
The bond between the NH
3
and H + is coordinate.
The bond between (NH
4
) + and (OH) is ionic.
What is the role of each of the following?
1.
The number of valence electrons in the strength of metallic bond. Egypt 2005
It was observed that the more electrons in the outermost energy level the strong the electron cloud and consequently the metallic bond
What is meant by the following?
1.
Coordinate bond. Egypt 2005
A type of covalent bond which differs only in the origin of the electron pair which are shared between atoms One atom is a donor and the other atom is an acceptor
2.
Amphoteric oxide. Egypt 2005
An oxide which acts either as a basic oxide or as an acidic oxide
3.
Pure covalent bond. Egypt 2006
A covalent bond which takes place between atoms of zero difference in electronegativity
4.
Hybridization. Egypt 2007
The overlap between two or more orbitals of the same atom to produce a number of new orbitals called hybridized orbitals
5.
Metalloids. Egypt 2007
Elements which have the appearance of metals and the chemical properties of nonmetals
6.
The electronic theory of valence. Egypt 2007
The covalent bond takes place as a result of the overlap between one orbital of one atom and one orbital of another atom
7.
Hybridization sp 2 . Egypt 2008
The overlap between an s orbital and two p orbitals http://pisscience.wikispaces.com/

Port Said International Schools
Better Education for Future Generations Grade: 11
Science Department Unit 3 Revision
8.
The molecular orbital theory. Egypt 2010
The molecular orbital theory considers the molecule as one big unit in which all atomic orbitals are combined together or hybridized forming molecular orbitals with the names sigma, beta and delta
Compare between the following Egypt 2007 - Egypt 2009 - Egypt 2010
-
Pi bond
A bond which is formed as a result of the overlap of two atomic orbitals side by side.
The pi bond is weak
Sigma bond
The bond which is formed as a result of the overlap of two atomic orbitals on one line (heat-to-head).
The sigma bond is stronger
Points of comparison
Type of hybridization
Methane
Sp 3
Ethene
Sp 2
Metallic bond
The bond that takes place as a result of the existence of an electron cloud of valence electrons which decreases the repulsion force between the positive metal ions in the crystal lattice.
Hydrogen bond
A bond that takes place as a result of the separation of charges in water molecule, so the molecules are attracted together.
The attraction between hydrogen and another atom of an element with high electronegativity

What are the inadequacies of the octet rule? Egypt 2007
The theory couldn't explain the covalent bond in some molecules such as the phosphorous pentachloride and boron trifluoride.
The theory couldn't explain the properties of the covalent compounds such as the sterostructure and the angles between the orbitals

Show by drawing only how the valence bond theory explains the bonding in hydrogen fluoride molecule. Egypt 2008
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……………………………………………………………………………………………… http://pisscience.wikispaces.com/

Port Said International Schools
Better Education for Future Generations Grade: 11
Science Department Unit 3 Revision
………………………………………………………………………………………………
…………………………………………………………………………………..
…………………………………………………………………………………..
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Choose from B and C which is suitable for column A: Egypt 2007
A
1.Valence bond theory.
B a. its formed as a result of the overlap of two atomic orbitals side by side
C
A.It considered the molecule as one unit
2.Sigma bond B.the overlapped orbitals are on one line.
3.Ionic bond. b.it was based on the conclusions of quantum mechanics. c.the atoms of all elements tend to reach the octet theory structure except hydrogen, lithium and beryllium
C.it explains the formation of the covalent bond. d.it is formed as a result of the overlap of atomic orbitals along an axis e. it is usually formed between metals and nonmetals.
D. its formed between chlorine and sodium in sodium chloride.
E. it is formed from the electron cloud of the free valence electrons.
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Correct the underlined words:
1.
Metalloids are characterized by their nearly filled valence shells with electrons and their electronegativity is greater than that of metals and nonmetals.
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………………………………………………………………………………………………. http://pisscience.wikispaces.com/