c4

Question 1

What are Group 1 metals also known as?

Answer 1

Group 1 metals are known as alkali metals

Question 2

Where are Group 1 elements located on the Periodic Table?

Answer 2

Group 1 elements are in the far-left vertical column of the Periodic Table.

Question 3

Why are Group 1 elements known as alkali metals?

Answer 3

They are called alkali metals because they react with water to form alkaline (basic) solutions.

Question 4

What are some typical physical properties of Group 1 metals?

Answer 4

Group 1 metals are shiny when freshly cut, soft enough to cut with a knife, have low density, are good conductors of electricity, and have relatively low melting points.

Question 5

Describe the general trend in density for Group 1 metals.

Answer 5

Density generally increases down the group, although sodium is less dense than expected.

Question 6

How does the melting point of Group 1 metals change as you go down the group?

Answer 6

The melting point decreases as you go down Group 1.

Question 7

Why are Group 1 metals stored in oil?

Answer 7

They are stored in oil to prevent them from reacting with oxygen and water in the air due to their high reactivity.

Question 8

What is the reaction of Group 1 metals with water?

Answer 8

Group 1 metals react with water to produce metal hydroxide and hydrogen gas. For example, sodium reacts with water to form sodium hydroxide and hydrogen:
2Na + H2O —> 2NaOH + H2

Question 9

How does reactivity change down Group 1?

Answer 9

Reactivity increases as you go down Group 1 because the outer electron is further from the nucleus and easier to lose.

Question 10

Describe lithium’s reaction with water.

Answer 10

Lithium fizzes steadily and slowly disappears when it reacts with water.

Question 11

Describe sodium’s reaction with water.

Answer 11

Sodium melts into a silvery ball, fizzes vigorously, and quickly disappears in water

Question 12

Describe potassium’s reaction with water.

Answer 12

Potassium immediately ignites with a lilac flame and quickly disappears when reacting with water.

Question 13

What is the general reactivity trend within Group 1 metals, and why?

Answer 13

Reactivity increases down the group because each element has one electron in the outer shell that is more easily lost as atomic size increases, weakening the attraction to the nucleus.

Question 14

Why does potassium react more vigorously than lithium in water?

Answer 14

Potassium reacts more vigorously because its outer electron is further from the nucleus and more easily lost compared to lithium, making it more reactive.

Question 15

How do you explain the oxidation of Group 1 metals in reactions?

Answer 15

Group 1 metals are oxidized in their reactions with water and non-metals, as they lose their outer electron to form positive ions.

Question 16

What role does the outer electron play in the reactivity of Group 1 metals?

Answer 16

The ease of losing the outer electron increases the reactivity of Group 1 metals, making elements lower in the group more reactive.

Question 17

What is a safety precaution when handling Group 1 metals?

Answer 17

Gloves are worn when handling these metals, and they are stored in oil to prevent reactions with air and water.

Question 18

Why might cesium react explosively with water?

Answer 18

Due to its high reactivity and ease of losing the outer electron, cesium reacts extremely violently with water.

Question 19

What is Group 7 also known as, and why?

Answer 19

Group 7 is also called the halogens. The name “halogen” comes from the Greek word for “salt-producing,” as these elements form salts when they react with metals.

Question 20

Where are the Group 7 elements found on the Periodic Table?

Answer 20

Group 7 (or Group 17 in IUPAC) elements are located in the second-to-last column on the right side of the Periodic Table.

Question 21

What are the physical states and colors of Group 7 elements at room temperature?

Answer 21

• Fluorine (F2): Pale yellow gas
• Chlorine (Cl2): Green gas
• Bromine (Br2): Orange-brown liquid that vaporizes easily
• Iodine (I2): Shiny grey-black crystalline solid that sublimates to a purple vapor

Question 22

Describe the general physical properties of halogens.

Answer 22

Halogens are non-metals with properties such as brittleness in the solid state and poor electrical conductivity.

Question 23

How does density change as you move down Group 7?

Answer 23

Density increases as you move down Group 7, with values as follows:

Question 24

How do melting and boiling points of the halogens change down the group?

Answer 24

Melting and boiling points increase as you go down Group 7.

Question 25

How do Group 7 elements typically react with metals?

Answer 25

Halogens react vigorously with metals to produce salts. For example, chlorine reacts with sodium to form sodium chloride:

Question 26

What is the trend in reactivity in Group 7?

Answer 26

Reactivity decreases as you go down Group 7. Fluorine is the most reactive, while iodine is less reactive.

Question 27

Why does reactivity decrease down Group 7?

Answer 27

Reactivity decreases because it becomes harder for larger atoms to gain an electron, as the outer electron shell is farther from the nucleus.

Question 28

What is the general equation for halogens gaining an electron?

Answer 28

x2 + 2e- —> 2x-

Question 29

Why is chlorine more reactive than iodine?

Answer 29

Chlorine’s atoms gain electrons more easily than iodine’s because chlorine has a smaller atomic radius, so the attraction between the nucleus and the electron is stronger.

Question 30

Describe an example of a displacement reaction involving halogens.

Answer 30

A more reactive halogen can displace a less reactive halogen from its compound. For example, chlorine can displace bromine from potassium bromide:

Question 31

Explain the color change when hot iron reacts with chlorine.

Answer 31

Iron reacts with chlorine to form iron(III) chloride, which has an orange-brown color.

Question 32

Why are Group 7 elements considered reduced in their reactions with metals?

Answer 32

Halogens are reduced when they react with metals because they gain electrons to form halide ions with a negative charge.

Question 33

How does the ease of gaining an electron change within Group 7?

Answer 33

It becomes harder to gain an electron as you go down the group because the atomic radius increases, weakening the attraction to the nucleus.

Question 34

What is a halogen displacement reaction?

Answer 34

A halogen displacement reaction is a reaction where a more reactive halogen displaces a less reactive halogen from its halide ions in solution.

Question 35

Provide an example of a halogen displacement reaction

Answer 35

Chlorine reacts with sodium bromide solution to form sodium chloride and bromine.

Question 36

What observable change occurs when chlorine displaces bromine from sodium bromide solution?

Answer 36

The reaction mixture turns orange-brown as bromine is produced

Question 37

In a halogen displacement reaction, what determines whether one halogen will displace another?

Answer 37

A more reactive halogen will displace a less reactive halogen from its halide ions in solution.

Question 38

List the reactivity order of chlorine, bromine, and iodine in halogen displacement reactions.

Answer 38

Chlorine is the most reactive, followed by bromine, then iodine.

Question 39

Why can chlorine displace bromine and iodine but not vice versa?

Answer 39

Chlorine is more reactive than bromine and iodine, so it can displace both from their halide ions, whereas bromine and iodine cannot displace chlorine

Question 40

Why is it safer to use solutions of halogens rather than pure elements in a school lab?

Answer 40

Solutions of chlorine, bromine, and iodine are safer to handle than the pure elements.

Question 41

Explain why bromine can displace iodine from sodium iodide solution.

Answer 41

Bromine is more reactive than iodine, allowing it to displace iodine from sodium iodide in a displacement reaction.

Question 42

What is a halide?

Answer 42

halide is a compound of a Group 7 (Group 17) element and one other element, often hydrogen or a metal (e.g., hydrogen chloride or sodium chloride).

Question 43

What is a halide ion?

Answer 43

A halide ion is a negative ion formed by a Group 7 (Group 17) element, such as chloride ions from chlorin

Question 44

How can you use halogen displacement reactions to confirm the order of reactivity for halogens?

Answer 44

By adding a halogen to various solutions of other halide ions and observing if displacement occurs, you can determine the relative reactivity of each halogen.

Question 45

Describe the procedure for a halogen displacement reaction practical.

Answer 45

1. Wearing eye protection, add a small volume of potassium chloride solution to a spotting tile.
2. Add a few drops of bromine water.
3. Note observations in a table.
4. Repeat for other pairs of halogens and halide solutions.

Question 46

Why should asthmatics take care when performing halogen displacement reactions?

Answer 46

Halogen fumes can be irritating, so asthmatics should avoid inhaling the

Question 47

In a practical setup for halogen displacement reactions, how do you choose which pairs of solutions to test?

Answer 47

Use solutions of potassium chloride, potassium bromide, and potassium iodide, and pair them with different halogens to confirm the order of reactivity.

Question 48

What is an ionic equation, and how does it relate to displacement reactions?

Answer 48

An ionic equation shows the ions involved in the reaction and can model what happens in displacement reactions by showing the exchange of ions.

Question 49

Write the ionic equation for chlorine displacing iodine from iodide ions.

Answer 49

Cl₂ + 2I⁻ → 2Cl⁻ + I₂

Question 50

Why are halogen displacement reactions considered redox reactions?

Answer 50

Halogen displacement reactions involve the transfer of electrons, where one halogen is reduced and the other is oxidized.

Question 51

How can ionic equations model displacement reactions in terms of redox?

Answer 51

Ionic equations show reduction and oxidation by combining half equations, illustrating the electron transfer between halogens.

Question 52

What is the word equation for the displacement reaction between chlorine and sodium iodide?

Answer 52

Chlorine + Sodium Iodide → Sodium Chloride + Iodine

Question 53

Predict whether iodine will displace astatine from sodium astatide and explain your reasoning.

Answer 53

Iodine will displace astatine from sodium astatide because iodine is more reactive than astatine.

Question 54

Describe the redox reaction when fluorine reacts with sodium chloride in a halogen displacement reaction.

Answer 54

Fluorine displaces chlorine from sodium chloride.
Reaction: F₂ + 2Cl⁻ → 2F⁻ + Cl₂
Explanation: Fluorine is reduced as it gains electrons, while chlorine is oxidized as it loses electrons.

Question 55

What are Group 0 elements, and where are they located?

Answer 55

Group 0 elements, also known as noble gases, are located in a vertical column on the far right of the Periodic Table. They are colorless, non-metals, and all are gases at room temperature.

Question 56

Why are noble gases called “noble”?

Answer 56

They are called noble gases because they are unreactive, similar to noble men and women of the past who didn’t take part in everyday activities. Noble gases rarely form compounds and have stable outer electron configurations.

Question 57

Why are noble gases unreactive?

Answer 57

Noble gases have complete outer electron shells, meaning they don’t have a tendency to gain, lose, or share electrons. This stability makes them very unreactive.

Question 58

What trends in properties do the noble gases show as you go down Group 0 ?

Answer 58

1. The attractive forces between atoms get stronger.
2. The boiling point increases as you go down the group.

Question 59

Why do noble gases have low densities?

Answer 59

Noble gases have low densities because their atoms are far apart in the gas state, resulting in very little mass in a given volume. As you go down Group 0, the density increases.

Question 60

What does the term ‘monatomic’ mean for noble gases?

Answer 60

Monatomic means that noble gases exist as single atoms rather than as molecules. They have weak forces of attraction between them, which are easily overcome by heating, giving them low boiling points.

Question 61

Why were noble gases previously called “inert gases”?

Answer 61

They were called “inert gases” because chemists believed they couldn’t react at all. However, this was disproved in 1962 when Neil Bartlett created the first noble gas compound, xenon hexafluoroplatinate (XePtF₆).

Question 62

What examples of noble gas uses are given in the text?

Answer 62

• Helium is used in weather balloons due to its low density and non-reactive properties.
• Noble gases in general are used in environments where non-reactivity is essential.

Question 63

Explain why the density of air at room temperature and pressure is 1.20 kg/m³. Compare this with the densities of helium and other noble gases in balloons.

Answer 63

Air is denser than helium (0.16 kg/m³) and other noble gases like neon (0.82 kg/m³), argon (1.64 kg/m³), krypton (3.75 kg/m³), and xenon (5.36 kg/m³), which allows helium to lift balloons as it is lighter than air.

Question 64

What caused the dinosaurs to become extinct, and how is it related to transition metals?

Answer 64

One theory is that an asteroid impact 65 million years ago caused the extinction of dinosaurs. The Earth’s crust contains an iridium-rich layer as evidence of this impact, as asteroids often have high iridium levels. Iridium and iron are examples of transition metals.

Question 65

What are transition metals, and where are they located on the Periodic Table?

Answer 65

Transition metals are elements located between Groups 2 and 3 on the Periodic Table, They are all metals and exhibit typical metallic properties.

Question 66

List some general properties of transition metals.

Answer 66

Transition metals are:
• Shiny with a fresh cut
• Good conductors of electricity
• Strong
• Malleable (can be bent or hammered into shape)

Question 67

How do transition metals compare to Group 1 alkali metals?

Answer 67

Compared to alkali metals of Group 1, transition metals:
1. Are stronger and harder.
2. Have higher densities.
3. Have higher melting points (except mercury, which is liquid at room temperature).

Question 68

Why are the properties of transition metals useful for everyday items?

Answer 68

Their strength, conductivity, and malleability make transition metals ideal for tools and construction. For example, copper is a good conductor of electricity and can be made into strong, flexible wires

Question 69

What are the chemical properties of transition metals?

Answer 69

• Transition metals are less reactive than alkali metals.
• They react slowly with water and oxygen.
• Iron rusts slowly, forming hydrated iron(III) oxide.
• Gold, platinum, and iridium do not react with water or oxygen.
• Transition metals produce colored ionic compounds, unlike alkali metals which produce white or colorless compounds.

Question 70

Describe the colors of different transition metal compounds as shown in Figure 4.

Answer 70

Aqueous solutions of transition metal compounds can have different colors:
• Copper sulfate is blue.
• Nickel chloride is green.
• Iron(II) sulfate is pale green.
• Iron(III) chloride is yellow.

Question 71

Explain the common ions formed by transition metals and how they are unique.

Answer 71

Unlike alkali metals that typically form only one positive ion, transition metals can form multiple positive ions.

Question 72

Why are platinum and gold used as catalysts in industrial processes?

Answer 72

Platinum and gold are transition metals that resist oxidation, even when hot. This property allows them to catalyze reactions without reacting themselves, making them valuable in industrial processes.

Question 73

Describe the oxidation states of transition metals and how they are used.

Answer 73

Transition metals can exhibit multiple oxidation states, allowing them to form a variety of compounds and ions. This versatility is valuable in industrial applications, especially in catalysis.

Question 74

What happens when a piece of copper wire is placed into silver nitrate solution?

Answer 74

The solution turns blue, and silver crystals form on the copper. This is a result of a metal displacement reaction where copper displaces silver from the solution.

Question 75

How do metals react with water and dilute acids?

Answer 75

Metals form positive ions in reactions. The ease of ion formation indicates a metal’s reactivity. Reactive metals react with:
1. Water to produce a metal hydroxide and hydrogen gas.
• Example: Ca + 2H_2O → Ca(OH)_2 + H_2
2. Dilute acids to produce a salt and hydrogen gas.
• Example: Ca + 2HCl → CaCl_2 + H_20

Question 76

What can the rate of reaction tell you about a metal’s reactivity?

Answer 76

The rate of reaction with water or dilute hydrochloric acid can be used to place metals in order of their reactivity. Faster hydrogen production indicates higher reactivity, seen as vigorous bubbling.

Question 77

How can you test a metal’s reactivity with water?

Answer 77

Add about 2 cm³ of water to a test tube with a small piece of metal. If bubbles are observed, the metal is reactive. If no bubbles appear, the metal is less reactive.

Question 78

Why should you avoid using boiling water or dilute hydrochloric acid when testing metal reactivity?

Answer 78

Boiling water or hydrochloric acid increases reaction speed, making the reactions potentially unsafe due to the risk of explosive or uncontrolled reactions.

Question 79

What is a metal displacement reaction?

Answer 79

A more reactive metal can displace a less reactive metal from its compound in solution. This occurs because the more reactive metal forms ions more easily, pushing out the less reactive metal.

Question 80

Provide example equations for metal displacement reactions.

Answer 80

1. Copper displacing silver:
2. Magnesium displacing zinc:

Question 81

What are oxidation and reduction in the context of displacement reactions?

Answer 81

In displacement reactions, the more reactive metal is oxidized (loses electrons), while the less reactive metal is reduced (gains electrons).

Question 82

How can the Periodic Table help predict reactivity patterns?

Answer 82

Reactivity patterns include:
1. Group 1 and Group 2 metals becoming more reactive down the group.
2. Transition metals generally being less reactive.
3. Non-metals in Group 7 becoming less reactive down the group.

Question 83

Why are Group 0 (noble gases) unreactive?

Answer 83

Group 0 elements have full outer electron shells, making them stable and generally unreactive.

Question 84

What is a practical setup for observing displacement reactions?

Answer 84

Place a small piece of metal in a solution containing ions of another metal, then observe any reaction such as color change or solid formation, which indicates a displacement reaction.

Question 85

Outline the steps to observe a metal displacement reaction using copper(II) sulfate

Answer 85

1. Place a small volume of copper(II) sulfate solution in a spotting tile well.
2. Add a piece of magnesium to the solution.
3. Observe any reaction, such as the formation of copper, indicating magnesium displaces copper.

Question 86

What trends can be observed in the reactivity series for Group 1, Group 2, and transition metals?

Answer 86

Groups 1 and 2, reactivity increases down the group. Transition metals are generally less reactive than Group 1 and Group 2 metals.

Question 87

Why can’t sodium and magnesium reactivity be compared directly?

Answer 87

Sodium and magnesium have different chemical properties and belong to different groups, making their reactivity responses different.

Question 88

How can you determine the reactivity of unknown metals?

Answer 88

React unknown metals with water, acids, and other metal ion solutions, and observe reaction rates and displacement effects to gauge reactivity.

Question 89

What is the purpose of the reactivity series?

Answer 89

The reactivity series arranges metals by reactivity, helping to predict their behavior in reactions like displacement and metal extraction.

Question 90

How can you test for the presence of oxygen gas?

Answer 90

Insert a glowing splint into the gas. If oxygen is present, the splint will relight.

Question 91

How can you test for the presence of hydrogen gas?

Answer 91

Hold a lit splint at the open end of a test tube containing the gas. If hydrogen is present, it will make a “pop” sound as it ignites.

Question 92

How can you test for the presence of carbon dioxide gas?

Answer 92

Bubble the gas through limewater (calcium hydroxide solution). If carbon dioxide is present, the limewater will turn cloudy (form a white precipitate of calcium carbonate).

Question 93

How can you test for the presence of chlorine gas?

Answer 93

Hold damp blue litmus paper in the gas. If chlorine is present, it will bleach the litmus paper, turning it white. (Note: The paper may turn red briefly before turning white.)

Question 94

How can you test for the presence of ammonia gas?

Answer 94

Hold damp red litmus paper in the gas. If ammonia is present, it will turn the red litmus paper blue. Additionally, ammonia has a strong, pungent smell.

Question 95

How can you test for the presence of sulfur dioxide gas?

Answer 95

Pass the gas through acidified potassium dichromate solution. If sulfur dioxide is present, the orange solution will turn green due to the reduction of dichromate ions.

Question 96

How can you test for the presence of water vapor?

Answer 96

Use cobalt(II) chloride paper, which is originally blue. If water vapor is present, the paper will turn pink.

Question 97

How can you recognize nitrogen dioxide gas?

Answer 97

Nitrogen dioxide has a characteristic brown color and a pungent, irritating smell. No specific simple test is used, but the color and odor are distinct.