مراجعة ليلة الامتحان كيمياءلغات ترم اول ثانى ثانوى علمى ازهرى

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. مراجعة ليلة الامتحان كيمياءلغات ترم اول ثانى ثانوى علمى ازهرى




مراجعة ليلة الامتحان كيمياءلغات ترم اول ثانى ثانوى علمى ازهرى
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Questions

1- The formula of silicon dioxide is ......... and the oxidation number of silicon in it is .........
2- The formula of beryllium hydride is ........., and the oxid. no. of Beryllium is ......... , while the formula of ammonia is ......... and the oxid. no. of nitrogen in it is …………..
3- The oxidation number of oxygen in most of its compounds is ......... but in peroxides is ……...... while in the elementary state is .........
4- The oxidation number of hydrogen in most of its compounds is ......... but in metal hydroxide is ……………..
5- The decrease of atomic radius of nonmetals leads to the ............ of ionization potential and electron affinity.

B- Write the scientific term (or rule which explains each of the following statements:
1- Numbers which identify the orbitals , their shape and their orientation.
3- Orbitals are filled with one electron first before gaining of electron tack place.
4- Each moving body is associated with a wave motion which has some of wave properties.
6- The elements where the (f) and (d) orbitals are occupied but not completely filled with electrons in their atomic or ionic state.
7- Electrons occupy the orbitals in the order of increasing orbital energy, the lowest energy orbitals are filled first.
8- Half the distance between the centers of two similar atoms in diatomic molecule.
10- The energy required to separate electrons less in connection by single atom in gaseous state.
11- The amount of energy released when an extra electron is added to a neutral gaseous atom .
12- The region of space around the nucleus where it is most probable to find the electron .


C- Choose the best answer:

1- The sublevel (d) contains ........ orbitals, it can accommodate up to ....... electron . (2 - 3 - 5 - 10 - 14)
2- An element of atomic number 10, the number of sublevels filled with electrons are ........... (2 - 3 - 5)
3- The valency shell of the atoms of fifth group elements contain .......... .
a) np4 b) np5 c) np d) np3
4- Group 5-A elements are classified as ............. block . (S-P-d-f)
5- Sublevel (f) saturated with number of electrons equals ..... .
a) 6 b) 16 c) 14 d) 32
6- The fourth energy level is saturated by a number of electrons equals ....... a) 8 b) 16 c) 32 d) 64
7- Electron affinity in group decrease .......... .
a) up on increasing atomic number only
b) up on decreasing atomic number only
c) up on increasing atomic volume only
d) a and c
8- The oxidation number of hydrogen in hydrogen molecule is (1, 2, 3, 0) and its oxidation number of hydrogen chloride is (1, 2, 3, 0).
9- The oxidation number of the first group elements equal ... .
a)+2 b)+l c)-2 d)-l
10- The oxidation number of oxygen in H2O2 is .......... .
a)+2 b)+l c)-2 d)-l
11- The atomic number of element is 29, so, its electronic structure is ......... .
a) (Ar) 3d10, 4S1
b) (Kr) 4P4, 5S2
c) (Xe) 6P6, 6S2




12- The electron affinity of Fluorine as compared to chlorine is ...........
a) Less b) more c) the same d) non of the above
13- The oxidation number of Sulphur in (SO4) is .......... .
a) 2+ b)4+ c)2- d) 6+
14- The metallic property increase in the group elements by .......... .
a) increasing of atomic number only .
b) increasing of ionic potential .
c) increasing of boiling degree .
d) when the radius decrease .
16- The element 86X, its electronic configuration in the outer most energy level is .......... .
a) 7S1 b) 3d5 c) 4S2, 4P5 d) 6S2, 6p6
17- The element X, its atomic number is 73 is considered from .......... series.
a) Lanthanides b) Main transition elements
c) Representative elements d) actinide
18- CO2is .......... oxide.
a) Amphoteric b) Acidic c) Neutral d) Basic
19- Na2O is .......... oxide .
a) Amphoteric b) Acidic c) Neutral d) Basic
20- A12 O3 is .......... oxide.
a) Amphoteric b) Acidic c) Neutral d) Basic
21- The element has the outer most electronic configuration 75 is found in ………
a) the first period, group 7 b) the six period, group 1
c) the seventh period, group 1 d) the six period, group 7
22- The spin quantum number (Ms) decide .......... .
a) Energy sublevel and their number
b) Number of electrons in each principle energy level
c) Direction of electron movement


23- The weakest acid is .......... .
a) HC1 b) HBr c) HF
24- Orbitals of the same energy sublevel are .......... .
a) different in energy but similar in shape
b) similar in energy but different in shape
c) similar in energy and shape
25- The oxidation number of oxygen in OF2 is .......... .
a) -2 b) -1 c) +2
26- The element having the electronic configuration (Ar) 3d5 4S1 is...........
a) Representative b) Inner transition c) Main transition
27- The maximum number of electrons that saturate, the energy level (n) is .......... .
a) 2n b) 2n2 c) 3n2
28- Elements of group III are of the block .......... .
a)S b)P c)d d)F
29- In Mosely periodic table, the elements are rearranged according to:
a) mass numbers b) atomic numbers
c)atomic weight d)a & b
30- The radius of the atom is :
a) the distance between the nucleus and the farthest electron in the atom,
b) half the distance between two combining atoms in a diatomic molecule,
c) the distance between the centers of two similar atoms in a diatomic molecule
d) half the distance between centers of two similar atoms in a diatomic molecule
31- In the same group as we go downwards the ionization energy:
a) increases b)decreases c) not change



difine:
Chemical reaction:
Ionic bond:
covalent Bond:
- Pure covalent:
- Polar covalent:
- Electronic theory of valency: (Octet rule Theory)
- The valency Bond Theory: (V.B.T.)
- Hybridization:
- Hydrogen bond :
- Molecular Orbital Theory: (M.O.T)
- Co – ordinate bond :-
Chemical reaction:
Is the reaction in which the bonds of reactants are broken forming new bonds in products.
- Ionic bond:
This bond is usually formed between metals and nonmetals. It is known
- covalent Bond:
- Formed between atoms of non-metals of the same element (have the same electronegativity) or between atoms of different elements have difference in E.N. less than 1.7 it occurs by sharing of valence electrons and is divided into two types:
- Pure covalent:
Formed between 2 similar atoms have the same E.N(difference in E.N = Zero)
- Polar covalent:
- Formed between 2 atoms have difference in E.N less than 1.7

(1) Electronic theory of valency: (Octet rule Theory)
Lewis and kosel scientist supposed that:
" all atoms of elements have tendency to reach the octet structure of the outer energy level for the nearest inert gas expect …….."



The valency Bond Theory: (V.B.T.)
Electrons has wave property so the formation of covalent bond as a result of overlapping of an atomic orbital of an atom with an unpaired electron, with another orbital in another orbital in another atom has an unpaired electron to form a molecular orbital contains a pair of electrons.
Hybridization:
"Is the combination of orbitals of close energy in the same atom to form a number of equivalent orbitals that can take part in chemical combination."
Molecular Orbital Theory: (M.O.T)
Considers the molecule as one unit (or a big atom with multi – nuclei) in which some of atomic orbitals of the combined atoms overlap forming molecular orbitals.
III – Co – ordinate bond :-
" is a type of covalent bond formed between 2 atoms on of theme has one
Orbital containing alone pair of electrons which is called donar atom , while The other atom has a vacant orbital called acceptor atom '
The lone pair of electrons are original from one atom .
IV – Hydrogen bond :
*is a bond formed between polar molecules in which hydrogen atoms lies between to atoms of high electron gativity as ( oxygen ) or ( fluorine ) , so the hydrogen atom binds with one atom by polar covalent bond and binds with the second atom by hydrogen bond .
V- Metallic Bond (between atoms of metal in the metallic structure):

"Is formed from electron cloud of the free valence electrons around (+ve) metal ions."


Give reasons:
On mixing iron fillings with sulphur the result will be a mixture not a compound.

Because: There is no chemical bond formed between iron and sulphur.
Solution of HCL in benzene does not conduct electricity, but its solution in H2O is a good conductor of electricity.

Because HCL is a polar covalent compound which can diffuse in benzene (non polar solvent) but can't be ionized into (+ve) ion (H+) & (-ve) ion (CL-), so it can't conduct electricity. While HCL in H2O (polar solvent) can be ionized into ions which can migrate to the opposite electrodes and so conducts electricity.
HCL + H2O H3O + + CL -

Although molecular weight of water (H2O) is very small (18) but it exists in a liquid state and boils at 100 C, while molecular weight of hydrogen sulphide (H2S) is (34) but it exists in a gaseous state and boils at (-61 C).
Due to the presence of big difference in E.N. between hydrogen and oxygen
and so formation of hydrogen bond between molecules of water.
Although sugar is covalent compound but it dissolves in water.
Due to formation of H2 bond between hydroxyl group of sugar & oxygen of
H2O, but its solution is a bad conductor of electricity because it can't be
ionized.
elements of group IA as Na are soft and have low melting point while
elements of group IIIA as AI are hard and have high melting point.
In case of Na: due to weak metallic bond which depends only on one electron from ns, while in case of Al: due to strong metallic bond which depends on three valency electrons of ns, np.
elements of 1st transition series are hard except Cu is relatively soft and has low melting point.
in case of T.E: due to strong metallic bond as it depends on electrons of 4s & 3d but Cu29 ( ) due to weak metallic bond which bond which depends only on one electron of 4S.



What are the Types of chemical bonds:

1) Ionic bond. 2) Covalent Bond.
3) Co-ordinate bond. 4) Hydrogen bond.
5) Metallic Bond.

Find the Example of ionic bond
: Formation of NaCl:

Na Na+ + e- Cl + e- Cl-
2, 8, 1 2, 8 2, 8, 7 2, 8, 8

Na+ + Cl - NaCl

Ionic bond is formed between atoms when the difference in E.N between them is higher than 1.7
As the difference in E.N. between atoms increases, the strength of the ionic bond increases which increases the melting point, boiling point and degree of conductivity.
What are the General properties of ionic compounds:

(1) Structure:
These are crystals that are condtructed of collections of cations and anions bound by electrostatic forces in crystal lattice containing the ion in a regular pattern.

(2) Melting and boiling points:
Ionic compounds generally have high melting and boiling points because a great amount of energy is needed to break down the crystal lattic and overcome the strong electrostatic attraction force between cations and anions.







What are the General properties of covalent compounds:
Electrical conductivity:
Ions are responsible for electrical conductivity in solutions. Since covalent compounds are not normally ionizable, so they do not conduct electric current as liquids or in aqueous solution.

Melting and boiling points:
Covalent compounds are characterized by their relatively low melting & boiling points due to the very weak attraction force between their molecules which needs low amount of thermal energy to be separated.
What are the Defects of electronic theory of valency:
It failed to explain the binding in many molecules.
Which No of e is around central atom is more or less in which than 8
In PCL5:
(ii) In BF3:
It couldn't explain some properties of molecules as stereo structure and angles between bonds.
Q: How does the valence bond theory explain the structure of methane?

There are 2 single electrons in carbon atom, but in methane molecule, the carbon atom forms 4 covalent bonds. So, the carbon atom must have 4 single electrons. How?? By exciting one electron from 2S to the vacant orbital 2P.
Now, the carbon atoms has 4 single electrons, but they aren't equivalent in energy as one electron is located in 2S orbital which is lower in energy than 2P orbital. Then they must be = in energy. How?? By hybridization between one orbital of 2S and 3 orbitals of 2P forming 4 orbitals equivalent in shape and energy.

Each of the hybridized orbitals in a carbon atom contains a (-ve) electron. These orbitals must go as far a part as possible from the other orbitals to decrease the repulsion forces between orbitals. When the angles between orbitals are 109 28, they will be more stable (less repulsive) compared to angles of 90 (an alternate structure). To complete the methane molecule, the four equivalent electrons of the four hybridized orbitals of the carbon atom can overlap with the 4(1S) electrons of the 4 hydrogen atom.


Explain methane Molecular Structure: (CH4):
Type of hybridization: SP3.

Angle between bonds: 109- 28

Stereo structure: tetrahedron pyramid.

Bonds: Single covalent bond of the type sigma.

4 (c – H ) bonds formed du to overlapping of 4SP3 orbitals of one carbon atom with 4( 1S) orbitals of 4 hydrogen atoms


Methane is chemically in active, due to the presence of 4 sigma bonds in its structure which are very strong (can't be broken easily), so great amount of energy is needed to break them down.


Professor


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