FORMULA, BONDING AND NOMENCLATURE.

 

1.a) Define the following terms:-

  i).Valence     

 ii) Chemical formula

 iii) Bond        

iv) Radical

b) Mention four types of Bond.

2.a) Give the properties of the:-  i) Covalent bond     ii) Ionic bond

   b) Give the difference between covalent bond and electrovalent bond at least four differences.

3.a) In terms of bonding and structures. Explain why metals are good conductors of electricity.

b) Use a dot (o) and cross (x) diagram to show how an atom of element T (atomic number 12) would combine with an atom of element S (atomic number 9).

 

4. State the type of structure formed when:-

  a) Potassium combines with fluorine

  b) Nitrogen combines with hydrogen.

  c) Carbon atoms combine using all the four valence explains.

5. a) Define a term compound?

   b) What are the rules to follow when writing chemical equation?

6. Explain why sodium chloride does not conduct electricity but molten and aqueous sodium chloride conducts electricity.

7. Diamond and graphite have giant covalent structures because of strong covalent bonds between their atoms.

(a). Explain why graphite is soft where as diamond is the hardest known natural substance.

(b)Explain why graphite has a much dower density then diamond.

 

8. The table below gives the atomic numbers of some elements the letters do not represent actual symbols.

 

Element	Atomic number
A	1
B	7
C	11
D	17

 

Identify two elements which will combine to give:-

a).An ionic compound

b)A covalent molecule.

9. Give three properties of substances with giant ionic structure.

10. Using a dot (.) and cross (x) diagram, show how a coordinate bond is formed in an ammonium ion. (N=7, H=1)

11.Element (x) atomic number =12, and element (Y) atomic number 1, combine to form a compound. Give three properties of the compound formed.

12.Phosphorus has an atomic number of 15. State the type of bond formed when phosphorus combine with bromine.

13.Covalent compounds are normally gaseous or liquid at room temperature, but iodine is a solid, yet it is covalently bonded. Explain.

14.Both methane (CH4) and diamond have covalent bonds. Explain why methane is a gas while diamond is a solid at room temperature.

15.Element M, relative atomic mass 40 and atomic number 20, reacts with cold water to liberate hydrogen gas. The element forms a chloride which conducts electricity in solution.

a)Show the difference between an M atom and M ion.

b)Determine the valency of M.

c)Write an equation for the reaction between M atom and water.

16.Explain the following observations.

a).Sodium nitrate dissolves in water but not in tetra chloromethane.

b).Paraffin wax does not dissolves in water but dissolves in tetra chloromethane .

c).A solution of hydrogen chloride in methylbenzene does not conduct electricity, but a solution of hydrogen chloride in water conducts electricity.

d).Solid sodium chloride does not conduct electricity but conducts when in solution or molten form.

e).Sodium metal is a good conductor of electricity while a piece of wood is a non-conductor.

17.An atom of element x (atomic number 11) and an atom of element Y (atomic number 9) combine to form a compound.

a).Write the formula of the compound

b).State the type of bond present in the compound

c).Identify the type of structure formed.

18. a) Define the following terms:-   i) Empirical formula      ii) Molecular formula

   b) Given 0.75g of Nitrogen combined with 0.8g of oxygen to form a Nitrogen oxide.   Calculate its molecular formula.

19. A hydrocarbon contain 75% of carbon and 25% of hydrogen calculate its molecular formula.

20.Write the chemical formula of the followings:-

a).Sodium chloride

b).Potassium hydroxide

c).Calcium oxide

d).Copper sulphate

e).Zinc carbonate

d).Magnesium sulphate

21. a) An element X is in group II of the periodic table.

      (i)State the type of bond that exist in the chloride of x.

     (ii)Write the formula of the ion formed by X.

    b) The nitrate of X was strongly heated.

     i) State what was observed

   ii)  Write an equation for the reaction.

22.a) Draw and name the structure adopted by the following substances.

    i) Diamond 

  ii) Sodium chloride

  b) i) State the physical properties of diamond.

     ii) What use is made of diamond as a result of one of the properties you slated above?

23. a) Write the formulae of the oxides of;   

    i) Sulphur   

    ii) Aluminum.

   b) State the type of bond that exists in the oxide of ;

   i)Sulphur 

   ii)Aluminum.

24. a) Sodium, aluminium and sulphur can combine with oxygen to form oxides. Copy and complete the following table to show the formula of class of, and bond in the oxide of each of these elements.

Element	Formula of oxide	Class of oxide	Type of bond in oxide.
Sodium
Aluminum
Sulphur

 

25.The electronic structure of an element X is 2;8;6.6.

a).Write the formula of the most common ion of X.

b).To which group of the periodic table does X belong?

c).Element X reacts with an element M.

   (Atomic number of M=122)

  (i)Draw the electronic structure of M.

  (ii)State the type of bond that exists in the compound between M and X.