Free Printable Lecture 4.3b

1.

Which group in the periodic table does silicon belong to?

a)

Group IV

b)

Group III

c)

Group V

d)

Group VI

2.

What is the oxidation number of silicon?

a)

+2

b)

+3

c)

+4

d)

+5

3.

Where are complex silicates found?

a)

In the atmosphere

b)

In the oceans

c)

In rocks, clays, and soils

d)

In living organisms

4.

How is the silicate tetrahedra structure made stable?

a)

By sharing electrons to form covalent bonds between Si and O

b)

By accepting electrons to form ionic bonds from other atoms

c)

By a combination of sharing and accepting electrons

d)

All of the above

5.

Which type of bonds are formed between Si and O in silicate tetrahedra?

a)

Ionic bonds

b)

Covalent bonds

c)

Metallic bonds

d)

Hydrogen bonds

6.

Silicates can consist of individual SiO₄ tetrahedra or these linked in which of the following forms?

a)

Chains, rings, sheets, or as a 3D covalent network

b)

Only chains

c)

Only rings

d)

Only sheets

7.

What is the purpose of positive ions in silicates?

a)

To balance the negative charge

b)

To increase the weight

c)

To decrease the melting point

d)

To enhance the color

8.

When transition elements are present in silicates, what is the usual effect on the mineral?

a)

The mineral is usually colored

b)

The mineral becomes transparent

c)

The mineral becomes brittle

d)

The mineral loses its luster

9.

What element is substituted for some of the silicon atoms in the silicate structure in aluminosilicates?

a)

Magnesium

b)

Aluminium

c)

Iron

d)

Calcium

10.

What is the ratio of (Al+Si):O in aluminosilicates compared to the parent silicate?

a)

It is higher

b)

It is lower

c)

It is the same

d)

It varies

11.

What effect does each aluminium substitution have on the charge of the anion in aluminosilicates?

a)

Increases the negative charge by one

b)

Decreases the negative charge by one

c)

Increases the positive charge by one

d)

Decreases the positive charge by one

12.

What is the overall charge on a silicate or aluminosilicate if cations are included in the formula?

a)

Positive

b)

Negative

c)

Zero

d)

Variable

13.

How can the charge on the anion of a silicate or aluminosilicate be calculated?

a)

By using the total charge on the cations

b)

By using the oxidation numbers of Si, O, and Al

c)

By using the total charge on the anions

d)

Both A and B

14.

What effect does the replacement of silicon with aluminium have on the silicate?

a)

It decreases the negative charge on the silicate.

b)

It increases the positive charge on the silicate.

c)

It increases the negative charge on the silicate.

d)

It has no effect on the charge of the silicate.

15.

What is the ability to attract and hold cations in soils dependent on?

a)

The amount of sand and the amount of clay present.

b)

The amount of humus and the amount of clay present.

c)

The amount of silt and the amount of clay present.

d)

The amount of water and the amount of clay present.

16.

What are soil silicates and aluminosilicates able to do?

a)

Adsorb H+ and release anions.

b)

Adsorb H+ and release cations.

c)

Adsorb OH- and release cations.

d)

Adsorb OH- and release anions.

17.

What is one reason clay particles can hold many cations?

a)

They are very small and have an extensive surface area.

b)

They are very large and have a small surface area.

c)

They are neutral and do not attract cations.

d)

They are hydrophobic and repel water.

18.

Why are the cations adsorbed onto the surface of clay particles not washed out of the root zone?

a)

Because they are chemically bonded to the clay particles.

b)

Because they are too heavy to be washed away.

c)

Because they are adsorbed onto the surface of the clay particles.

d)

Because they are repelled by water.

19.

What is the benefit of cations being adsorbed onto the surface of clay particles for plants?

a)

They are available to plants as required.

b)

They are permanently fixed and cannot be used by plants.

c)

They are converted into anions.

d)

They are washed away easily.

20.

What type of reaction exists between adsorbed cations and cations in soil water?

a)

$A)Static\ equilibrium$

b)

$B)Dynamic\ equilibrium$

c)

$C)Exothermic$

d)

$D)Endothermic$

21.

Which of the following is an example of cation exchange between the same cation?

a)

$A) Ca^{2+}_{(clay)} \rightleftharpoons Ca^{2+}_{(aq)}$

b)

$B) Ca^{2+}_{(aq)} + 2K^{+}_{(clay)} \rightleftharpoons 2K^{+}_{(aq)} + Ca^{2+}_{(clay)}$

c)

$C) Na^{+}_{(clay)} \rightleftharpoons Na^{+}_{(aq)}$

d)

$D) Mg^{2+}_{(clay)} \rightleftharpoons Mg^{2+}_{(aq)}$

22.

What is the process called when cations in soil water exchange with adsorbed cations?

a)

$A) Ionization$

b)

$B) Precipitation$

c)

$C) Cation exchange$

d)

$D) Neutralization$

23.

Which of the following reactions represents cation exchange between different cations?

a)

$A) Ca^{2+}_{(clay)} \rightleftharpoons Ca^{2+}_{(aq)}$

b)

$B) Ca^{2+}_{(aq)} + 2K^{+}_{(clay)} \rightleftharpoons 2K^{+}_{(aq)} + Ca^{2+}_{(clay)}$

c)

$C) Na^{+}_{(clay)} \rightleftharpoons Na^{+}_{(aq)}$

d)

$D) Mg^{2+}_{(clay)} \rightleftharpoons Mg^{2+}_{(aq)}$

Lecture 4.3b

Total questions: 23

Worksheet time: 12mins

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