PERIODICITY 2 [IB]

 

1.       Which equation represents the third ionization energy of an element M?

A.      M⁺(g) → M⁴⁺(g) + 3e^–

B.      M²⁺(g) → M³⁺(g) + e^–

C.      M(g) → M³⁺(g) + 3e^–

D.      M³⁺(g) → M⁴⁺(g) + e^–

ANSWER

(Total 1 mark)

 

 

2.       Silicon tetrachloride, SiCl₄, reacts with water to form an acidic solution.

(i)      Explain why silicon tetrachloride has a low melting point.

ANSWER

(2)

(ii)      Write an equation for the reaction of silicon tetrachloride with water.

ANSWER

(1)

(Total 3 marks)

 

 

3.       By reference to the structure and bonding in NaCl and SiCl₄:

(i)      State and explain the differences in electrical conductivity in the liquid state.

(3)

(ii)      Predict an approximate pH value for the solutions formed by adding each compound separately to water. Explain your answer.

(4)

ANSWER

(Total 7 marks)

 

 

4.       Which pair would react together most vigorously?

A.      Li and Cl₂

B.      Li and Br₂

C.      K and Cl₂

D.      K and Br₂

ANSWER

(Total 1 mark)

 

 

5.       Which general trends are correct for the oxides of the period 3 elements (Na₂O to Cl₂O)?

I.       Acid character decreases.

II.      Electrical conductivity (in the molten state) decreases.

III.     Bonding changes from ionic to covalent.

A.      I and II only

B.      I and III only

C.      II and III only

D.      I, II and III

ANSWER

(Total 1 mark)

 

 

6.       (a)     Classify each of the following oxides as acidic, basic or amphoteric.

(i)      aluminium oxide

        
ANSWER

(1)

 

(ii)     sodium oxide

        
ANSWER

(1)

 

(iii)     sulfur dioxide

        
ANSWER

(1)

 

(b)     Write an equation for each reaction between water and

(i)      sodium oxide

ANSWER

(1)

 

(ii)     sulfur dioxide.

ANSWER

(1)

(Total 5 marks)

 

 

7.       Which properties are typical of most non-metals in period 3 (Na to Ar)?

I.       They form ions by gaining one or more electrons.

II.      They are poor conductors of heat and electricity.

III.     They have high melting points.

A.      I and II only

B.      I and III only

C.      II and III only

D.      I, II and III

ANSWER

(Total 1 mark)

 

 

8.       Discuss the acid-base nature of the period 3 oxides. Write an equation to illustrate the reaction of one of these oxides to produce an acid, and another equation of another of these oxides to produce a hydroxide.

ANSWER

(Total 5 marks)

 

 

9.       Which compound of an element in period 3 reacts with water to form a solution with a pH greater than 7?

A.      SiO₂

B.      SiCl₄

C.      NaCl

D.      Na₂O

ANSWER

(Total 1 mark)

 

 

10.     Information about the halogens appears in the Data Booklet.

(i)      Explain why the ionic radius of chlorine is less than that of sulfur.

ANSWER

(2)

(ii)      Explain what is meant by the term electronegativity and explain why the electronegativity of chlorine is greater than that of bromine.

(3)

ANSWER

(Total 5 marks)