Topic: Metal Reactivity & Halogens

Metal Reactivity & Halogens quiz

1. An experiment investigates which of metals X and Z is more reactive. The result is X + ZSO₄ → XSO₄ + Z. Which metal is more reactive?

Question 1 of 23

2. Write the word equation to represent the reaction between sulfuric acid and magnesium

Question 2 of 23

3. Where are non-metals found on the periodic table?

Question 3 of 23

4. Are metal oxides acidic or basic?

Question 4 of 23

5. Explain, by referring to the electronic configurations, why fluorine is more reactive than chlorine

Question 5 of 23

6. State the meaning of the term redox

Question 6 of 23

7. How many electrons in the outer shell of group 3 elements?

Question 7 of 23

8. In the test of a gas, a lit splint gives a squeaky pop. What is the gas?

Question 8 of 23

9. Which is more reactive: silver, gold, copper or iron?

Question 9 of 23

10. On the Periodic Table what is the meaning of the word Period?

Question 10 of 23

11. Why do elements in the same group of the periodic table have similar chemical properties?

Question 11 of 23

12. What colour and state is bromine at room temperature?

Question 12 of 23

13. Put these 3 alkali metals in order of reactivity, starting with the most reactive: potassium, francium, lithium

Question 13 of 23

14. Write the word equation for the formation of rust

Question 14 of 23

15.

If 2 similar test tubes contain acid, and a different metal sample is added to each, how might you tell which metal is more reactive?

Question 15 of 23

16. On the Periodic table what is the meaning of the word Group? What does that tell us about the electron configuration of the atom?

Question 16 of 23

17. Explain, by referring to the electronic configurations, why lithium is less reactive than sodium.

Question 17 of 23

18. Describe how reactivity changes as you descend group 7

Question 18 of 23

19.

If pieces of lithium, potassium and sodium were cut and exposed to air, how could observations of the different reactions indicate the relative reactivity of those 3 metals?

Question 19 of 23

20. What is sacrificial protection?

Question 20 of 23

21. What are the elements in group 0 called?

Question 21 of 23

22. Predict what colour and state is astatine at room temperature

Question 22 of 23

23. State 5 observations when sodium reacts with water

Question 23 of 23


 

2020-02-16T16:50:09+00:00Categories: Uncategorized|Tags: , |

1:18 understand how elements are arranged in the Periodic Table: in order of atomic number, in groups and periods

The elements in the Periodic Table are arranged in order of increasing atomic number.

 

Image result for periodic table groups and periods

Columns are called Groups. They indicate the number of electrons in the outer shell of an atom.

Rows are called Periods. They indicate the number of shells (energy levels) in an atom.

1:19 understand how to deduce the electronic configurations of the first 20 elements from their positions in the Periodic Table

Electrons are found in a series of shells (or energy levels) around the nucleus of an atom.

Each energy level can only hold a certain number of electrons. Low energy levels are always filled up first.

Rules for working out the arrangement (configuration) of electrons:

Example – chlorine (Cl)

1) Use the periodic table to look up the atomic number. Chlorine’s atomic number (number of protons) is 17.

2) Remember the number of protons = number of electrons. Therefore chlorine has 17 electrons.

3) Arrange the electrons in levels (shells):

  • 1st shell can hold a maximum of 2
  • 2nd can hold a maximum of 8
  • 3rd can also hold 8

Therefore the electron arrangement for chlorine (17 electrons in total) will be written as 2,8,7

4) Check to make sure that the electrons add up to the right number

The electron arrangement can also be draw in a diagram.

Electron arrangement for the first 20 elements:

1:20 understand how to use electrical conductivity and the acid-base character of oxides to classify elements as metals or non-metals

Metals

  • conduct electricity
  • have oxides which are basic, reacting with acids to give a salt and water

 

Non – Metals

  • do not conduct electricity (except for graphite)
  • have oxides which are acidic or neutral

 

1:21 identify an element as a metal or a non-metal according to its position in the Periodic Table

Metals on the left of the Periodic Table.

Non-Metals on the top-right, plus Hydrogen.

1:22 understand how the electronic configuration of a main group element is related to its position in the Periodic Table

Elements in the same group have the same number of electrons in their outer shell.

This is why elements from the same group have similar properties.

1:23 Understand why elements in the same group of the Periodic Table have similar chemical properties

Elements in the same group of the periodic table have the same number of electrons in their outer shells, which means they have similar chemical properties.

2:01 understand how the similarities in the reactions of lithium, sodium and potassium with water provide evidence for their recognition as a family of elements

Group 1 metals such as potassium, sodium and lithium, react with water to produce a metal hydroxide and hydrogen. For example:

          lithium   +   water   →   lithium hydroxide   +   hydrogen

          2Li (s)   +   2H₂O (l)   →   2LiOH (aq)   +   H₂ (g)

The observations for the reaction of water with either potassium or sodium or lithium have the following similarities:

  1. fizzing (hydrogen is produced)
  2. metal floats and moves around on the water
  3. metal disappears

In each case a metal hydroxide solution is produced.

These similarities in the reactions provide evidence that the 3 metals are in the same group of the Periodic Table (i.e. have the same number of electrons in their outer shell).

2:02 understand how the differences between the reactions of lithium, sodium and potassium with air and water provide evidence for the trend in reactivity in Group 1

Lithium is the first element in group 1 of the Periodic Table. The observations for the reaction of lithium and water are:

  1. fizzing (hydrogen gas is released)
  2. lithium floats and moves around on the water
  3. lithium disappears

Sodium is the second alkali metal in the group. The reaction of sodium and water is more vigorous than lithium’s:

  1. fizzing (hydrogen gas is released)
  2. sodium floats and moves around on the water
  3. sodium melts into a silver-coloured ball
  4. sodium disappears

Potassium is the third alkali metal in the group. The reaction of potassium and water is more vigorous than sodium’s:

  1. fizzing (hydrogen gas is released)
  2. potassium floats and moves around on the water
  3. catches fire with a LILAC flame
  4. potassium disappears

When the group 1 metals react with air they oxidise, showing a similar trend in reactivity as we go down the group of the Periodic Table.

Therefore, as we go down group 1 (increasing atomic number), the elements become more reactive: Li<Na<K<Rb<Cs<Fr

2:03 use knowledge of trends in Group 1 to predict the properties of other alkali metals

From the data in the table, it is possible to deduce the properties of francium from the trends in the other group 1 metals.

For example, we can predict that francium will have a melting point around 20⁰C and a density of just over 2g/cm³.

We can also predict that francium will react violently with water, producing francium hydroxide and hydrogen.

Alkali metalMelting point (⁰C)Density (g/cm³)Reaction with waterProducts
lithium (Li)1810.53fizzinglithium hydroxide + hydrogen
sodium (Na)980.97rapid fizzingsodium hydroxide + hydrogen
potassium (K)630.86vigorous fizzing and lilac flamepotassium hydroxide + hydrogen
rubidium (Rb)391.53?rubidium hydroxide + hydrogen
caesium(Cs)291.88?caesium hydroxide + hydrogen
francium (Fr)????

2:04 (Triple only) explain the trend in reactivity in Group 1 in terms of electronic configurations

As you go down the group the outer electron lost from the group 1 metal is further from the nucleus therefore the electron is less attracted by the nucleus and therefore more easily lost.

2:05 know the colours, physical states (at room temperature) and trends in physical properties of chlorine, bromine and iodine

ElementColourState at room temp
Chlorine (Cl2)GreenGas
Bromine (Br2)RedLiquid
Iodine (l2)GreySolid

Chlorine is a toxic gas, so should be handled in a fume cupboard.

2:06 use knowledge of trends in Group 7 to predict the properties of other halogens

If you look at the trends in the physical properties of the halogens, Cl2, Br2, I2 you can make predictions about the properties of the other halogens.

ElementColourState at room temp
Fluorine (F2)YellowGas
Astatine (At2)BlackSolid

2:07 understand how displacement reactions involving halogens and halides provide evidence for the trend in reactivity in Group 7

Group 7 elements are called the Halogens. As you go up group 7 (decreasing atomic number), the elements become more reactive. For example, fluorine is the most reactive and astatine is the least reactive.

 

A more reactive halogen will displace a less reactive halogen, e.g. chlorine will displace bromine:

By reacting a halogen solution with a potassium halide solution and making observations, the order of their reactivity can be deduced:

Potassium chloride, KCl(aq)Potassium bromide, KBr(aq)Potassium iodide, KI(aq)
Chlorine, Cl2(aq)No changeColourless to orangeColourless to brown
Bromine, Br2(aq)No changeNo changeColourless to brown
Iodine, I2(aq)No changeNo changeNo change

From the above results, chlorine displaces both bromine and iodine, and bromine displaces iodine. Therefore the order of reactivity is: chlorine is more reactive than bromine, which in turn is more reactive than iodine.

2:08 (Triple only) explain the trend in reactivity in Group 7 in terms of electronic configurations

The higher up we go in group 7 (halogens) of the periodic table, the more reactive the element. The explanation concerns how readily these elements form ions, by attracting a passing electron to fill the outer shell.

In fluorine the outer electron shell is very close to the positively charged nucleus, so the attraction between this nucleus and the negatively charged electrons is very strong. This means fluorine is very reactive indeed.

However, for iodine the outer electron shell is much further from the nucleus so the attraction is weaker. This means iodine is less reactive.

2:15 understand how metals can be arranged in a reactivity series based on their reactions with: water and dilute hydrochloric or sulfuric acid

Some metals are more reactive than others.

The order of reactivity can be determined by adding acid to different metals and observing the rate of reaction.

For example, when hydrochloric acid is added to iron (Fe) then bubbles of hydrogen are produced slowly. However, if the same acid is added to zinc (Zn) then bubbles will be produced more quickly. This tells us that zinc is more reactive than iron.

Instead of using acid, water can be used to test the relative reactivity of metals. However, many metals are too low in the reactivity series to react with water

2:16 understand how metals can be arranged in a reactivity series based on their displacement reactions between: metals and metal oxides, metals and aqueous solutions of metal salts

A metal will displace another metal from its oxide that is lower in the reactivity series. For example, a reaction with magnesium and copper (II) oxide will result in the magnesium displacing the copper from its oxide:

A metal will also displace another metal from its salt that is lower in the reactivity series. For example, the reaction between zinc and copper (II) sulfate solution will result in zinc displacing the copper from its salt:

The blue colour of the copper (II) sulfate solution fades as colourless zinc sulfate solution is formed.

2:17 know the order of reactivity of these metals: potassium, sodium, lithium, calcium, magnesium, aluminium, zinc, iron, copper, silver, gold

A more reactive metal will displace a less reactive metal.

In addition a more reactive metal will react more vigorously than a less reactive metal.

For example, potassium takes a shorter time to react than sodium:

2:19a understand how the rusting of iron may be prevented by: barrier methods, galvanising

Barrier Methods: Rusting may be prevented by stopping the water and oxygen getting to the iron with a barrier of grease, oil, paint or plastic.

Galvanising: (coating in zinc) also prevents water and oxygen getting to the iron, but with galvanising even if the barrier is broken the more reactive zinc corrodes before the less reactive iron. During the process, the zinc loses electrons to form zinc ions.

 

2:19 understand how the rusting of iron may be prevented by: barrier methods, galvanising and sacrificial protection

Barrier Methods: Rusting may be prevented by stopping the water and oxygen getting to the iron with a barrier of grease, oil, paint or plastic.

Galvanising: (coating in zinc) also prevents water and oxygen getting to the iron, but with galvanising even if the barrier is broken the more reactive zinc corrodes before the less reactive iron. During the process, the zinc loses electrons to form zinc ions.

Sacrificial Protection: Zinc blocks are attached to iron boat hulls and underground pipelines to act as sacrificial anodes. Zinc is more reactive than iron, so oxygen in the air reacts with the zinc to form a layer of zinc oxide instead of the iron.

2:20 in terms of gain or loss of oxygen and loss or gain of electrons, understand the terms: oxidation, reduction, redox, oxidising agent, reducing agent, in terms of gain or loss of oxygen and loss or gain of electrons

Oxidation

  • Oxidation is the loss of electrons. For example a sodium atom (Na) loses an electron to become a sodium ion (Na⁺). Another example is a chloride ion (Cl⁻) losing an electron to become a chlorine atom (Cl).
  • Another definition of oxidation is the gain of oxygen. For example if carbon combines with oxygen to form carbon dioxide, the carbon is being oxidised.

 

Reduction

  • Reduction is the gain of electrons. For example a sodium ion (Na⁺) gains an electron to become a sodium ion (Na). Another example is a chlorine atom (Cl) gaining an electron to become a chloride atom (Cl⁻).
  • Another definition of reduction is the loss of oxygen. For example when aluminium oxide is broken down to produce aluminium and oxygen, the aluminium is being reduced.

 

Redox: A reaction involving oxidation and reduction.

A good way to remember the definitions of oxidation and reduction in terms of electrons is:

  • OILRIG : Oxidation Is the Loss of electrons and Reduction Is the Gain of electrons

 

Oxidising agent: A substance that gives oxygen or removes electrons (it is itself reduced).

 

Reducing agent: A substance that takes oxygen or gives electrons (it is itself oxidised).

 

2:21 practical: investigate reactions between dilute hydrochloric and sulfuric acids and metals (e.g. magnesium, zinc and iron)

Metals which are above hydrogen in the reactivity series will react with dilute hydrochloric or sulfuric acid to produce a salt and hydrogen.

metal   +   acid   →   salt   +   hydrogen

For example:

         magnesium   +   hydrochloric acid   →   magnesium chloride   +   hydrogen

         Mg (s)         +         2HCl (aq)         →         MgCl₂ (aq)         +         H₂ (g)

This is a displacement reaction.

Image result for magnesium + hydrochloric acid

There is a rapid fizzing and a colourless gas is produced. This gas pops with a lighted splint, showing the gas is hydrogen.

The reaction mixture becomes warm as heat is produced (exothermic).

The magnesium disappears to leave a colourless solution of magnesium chloride.

If more reactive metals are used instead of magnesium the reaction will be faster so the fizzing will be more vigorous and more heat will be produced.

2:44 describe tests for these gases: hydrogen, oxygen, carbon dioxide, ammonia, chlorine

Tests for gases

GasTestResult if gas present
hydrogen (H2)Use a lit splintGas pops
oxygen (O2)Use a glowing splintGlowing splint relights
carbon dioxide (CO2)Bubble the gas through limewaterLimewater turns cloudy
ammonia (NH3)Use red litmus paperTurns damp red litmus paper blue
chlorine (Cl2)Use damp litmus paperTurns damp litmus paper white (bleaches)
Select a set of flashcards to study:

     Terminology

     Skills and equipment

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Section 1: Principles of chemistry

      a) States of matter

      b) Atoms

      c) Atomic structure

     d) Relative formula masses and molar volumes of gases

     e) Chemical formulae and chemical equations

     f) Ionic compounds

     g) Covalent substances

     h) Metallic crystals

     i) Electrolysis

 Section 2: Chemistry of the elements

     a) The Periodic Table

     b) Group 1 elements: lithium, sodium and potassium

     c) Group 7 elements: chlorine, bromine and iodine

     d) Oxygen and oxides

     e) Hydrogen and water

     f) Reactivity series

     g) Tests for ions and gases

Section 3: Organic chemistry

     a) Introduction

     b) Alkanes

     c) Alkenes

     d) Ethanol

Section 4: Physical chemistry

     a) Acids, alkalis and salts

     b) Energetics

     c) Rates of reaction

     d) Equilibria

Section 5: Chemistry in industry

     a) Extraction and uses of metals

     b) Crude oil

     c) Synthetic polymers

     d) The industrial manufacture of chemicals

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