1. KNOCKHARDY PUBLISHING
GROUP 1
The alkali metals
National 5 Chemistry
KNOCKHARDY PUBLISHING

2. GROUP I www.knockhardy.org.uk INTRODUCTION
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3. GROUP I CONTENTS Introduction Group trends Group similarities
Flame tests
Reaction with water
Reaction with halogens
Summary
Quick quiz

4. INTRODUCTION

5. THE ALKALI METALS ARE IN GROUP I OF THE PERIODIC TABLE
INTRODUCTION
THE ALKALI METALS ARE IN GROUP I OF THE PERIODIC TABLE
Group Li Na K Rb Cs Fr

6. THE ALKALI METALS ARE IN GROUP I OF THE PERIODIC TABLE
INTRODUCTION
THE ALKALI METALS ARE IN GROUP I OF THE PERIODIC TABLE
Group Li Na K Rb Cs Fr
THEY ARE VERY REACTIVE METALS AND HAVE ELECTRONIC CONFIGURATIONS WITH ONE ELECTRON IN THE OUTER SHELL

7. GROUP PROPERTIES • exist as separate diatomic molecules… eg Cl2
GENERAL • metals
• exist as separate diatomic molecules… eg Cl2
• have one electron in their outer shell
• form positive ions with a 1+ charge
• vigorous reaction with water and halides

8. GROUP PROPERTIES • exist as separate diatomic molecules… eg Cl2
GENERAL • metals
• exist as separate diatomic molecules… eg Cl2
• have one electron in their outer shell
• form positive ions with a 1+ charge
• vigorous reaction with water and halides
TRENDS • melting point
• hardness
• electronic configuration
• atomic size
• ionic size
• reactivity

9. GROUP TRENDS

10. GROUP TRENDS APPEARANCE Li Na K Rb Cs Appearance Grey solid Grey solid
Density / gcm-3
0.53
0.97
0.86
1.53
1.87
Flame test
Crimson
Yellow
Lilac
Red-violet
Blue-violet

11. GROUP TRENDS APPEARANCE MELTING POINTLi Na K Rb Cs
Appearance
Grey solid
Grey solid
Grey solid
Grey solid
Grey solid
Density / gcm-3
0.53
0.97
0.86
1.53
1.87
Flame test
Crimson
Yellow
Lilac
Red-violet
Blue-violet
MELTING POINT Li Na K Rb Cs
Melting point / °C
180.7 98
63.8
39.2
43.2
DECREASES down Group as the atoms get larger

12. ELECTRONIC CONFIGURATION
GROUP TRENDS
ELECTRONIC CONFIGURATION Li Na K Rb Cs
Atomic Number 3 11 19 37 55
Configuration
2,1
2,8,1
2,8,8,1
2,8,18,8,1
2,8,18,18,8,1

13. ELECTRONIC CONFIGURATION
GROUP TRENDS
ELECTRONIC CONFIGURATION Li Na K Rb Cs
Atomic Number 3 11 19 37 55
Configuration
2,1
2,8,1
2,8,8,1
2,8,18,8,1
2,8,18,18,8,1
• electrons go into shells further from the nucleus
19+
11+ 3+
LITHIUM
2,1
SODIUM
2,8,1
POTASSIUM
2,8,8,1

14. GROUP TRENDS ATOMIC RADIUS Li Na K Rb Li Na K Rb Cs Atomic radius / nm
0.152
0.185
0.227
0.247
0.265 Li Na K Rb Cs

15. GROUP TRENDS ATOMIC RADIUS Li Na K RbCs
Atomic radius / nm
0.152
0.185
0.227
0.247
0.265 Li Na K Rb Cs
ATOMIC RADIUS INCREASES down Group
• the greater the atomic number the more electrons there are;
these go into shells increasingly further from the nucleus

16. GROUP TRENDS ATOMIC & IONIC RADIUS Li Na K Rb K+ Rb+Cs
Atomic radius / nm
0.152
0.185
0.227
0.247
0.265 Li Na K Rb Cs
Li+
Na+ K+
Rb+
Cs+
Ionic radius / nm
0.068
0.098
0.133
0.148
0.167
Li+
Na+ K+
Rb+
Cs+
IONIC RADIUS INCREASES down Group
• ions are smaller than atoms - the removal of an electron
means that there are now fewer shells

17. GROUP SIMILARITIES

18. GROUP SIMILARITIES ION FORMATION Li Na K Rb Cs Ion Li+ Na+ K+ Rb+ Cs+
Configuration 2
2,8
2,8,8
2,8,18,8
2,8,18,18,8

19. GROUP SIMILARITIES ION FORMATIONLi Na K Rb Cs
Ion
Li+
Na+ K+
Rb+
Cs+
Configuration 2
2,8
2,8,8
2,8,18,8
2,8,18,18,8
• atoms ‘lose’ one electron to form a positive ion of charge 1+
• ions are smaller than atoms
• the larger the atom the easier it forms an ion because the
electron being removed is further from the nucleus

20. GROUP SIMILARITIES ION FORMATIONLi Na K Rb Cs
Ion
Li+
Na+ K+
Rb+
Cs+
Configuration 2
2,8
2,8,8
2,8,18,8
2,8,18,18,8
• atoms ‘lose’ one electron to form a positive ion of charge 1+
• ions are smaller than atoms
• the larger the atom the easier it forms an ion because the
electron being removed is further from the nucleus
11+
11+
SODIUM ATOM
11 PROTONS
11 ELECTRONS
SODIUM ION
11 PROTONS
10 ELECTRONS

21. Increasingly reactive
GROUP SIMILARITIES
ION FORMATION Li Na K Rb Cs
Ion
Li+
Na+ K+
Rb+
Cs+
Configuration 2
2,8
2,8,8
2,8,18,8
2,8,18,18,8
• atoms ‘lose’ one electron to form a positive ion of charge 1+
• ions are smaller than atoms
• the larger the atom the easier it forms an ion because the
electron being removed is further from the nucleus
REACTIVITY Li Na K Rb Cs
Increasingly reactive
• reactivity increases down the Group as atoms get larger

22. FLAME TESTS

23. FLAME TESTS SOME METALS CAN BE IDENTIFIED BY FLAME TESTS
A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME
THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY
THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT

24. Cu Na Ba K Ca FLAME TESTS SOME METALS CAN BE IDENTIFIED BY FLAME TESTS
A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME
THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY
THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT
Cu Na Ba K Ca
NORMAL
BUNSEN
BLUE BRIGHT APPLE LILAC BRICK
GREEN YELLOW GREEN RED

25. FLAME TESTS SOME METALS CAN BE IDENTIFIED BY FLAME TESTS
A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME
THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY
THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT
A LINE SPECTRUM IS PRODUCED

26. FLAME TESTS SOME METALS CAN BE IDENTIFIED BY FLAME TESTS
A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME
THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY
THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT
A LINE SPECTRUM IS PRODUCED
CONTINUOUS SPECTRUM

27. FLAME TESTS SOME METALS CAN BE IDENTIFIED BY FLAME TESTS
A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME
THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY
THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT
A LINE SPECTRUM IS PRODUCED
CONTINUOUS SPECTRUM
LINE SPECTRUM

28. EACH METAL HAS ITS OWN CHARACTERISTIC LINE SPECTRUM
FLAME TESTS
SOME METALS CAN BE IDENTIFIED BY FLAME TESTS
A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME
THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY
THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT
A LINE SPECTRUM IS PRODUCED
CONTINUOUS SPECTRUM
LINE SPECTRUM
EACH METAL HAS ITS OWN CHARACTERISTIC LINE SPECTRUM

29. REACTIONS OF ALKALI METALS

30. REACTIONS OF ALKALI METALS
REACTIVITY INCREASES DOWN THE GROUP
The further the outer shell electron is from the nucleus, the easier it is to remove and the easier it becomes to form a positive ion.
Because of this, alkali metals get more reactive as you go down the group.

31. REACTIONS OF ALKALI METALS
REACTIVITY INCREASES DOWN THE GROUP
The further the outer shell electron is from the nucleus, the easier it is to remove and the easier it becomes to form a positive ion.
Because of this, alkali metals get more reactive as you go down the group.
GETS INCREASINGLY EASIER TO REMOVE THE OUTER SHELL ELECTRON 3+
11+
19+
LITHIUM
2,1
SODIUM
2,8,1
POTASSIUM
2,8,8,1

32. REACTION WITH WATER

33. REACTION WITH WATER GROUP I METALS REACT WITH COLD WATER
THE REACTIVITY INCREASES DOWN THE GROUP
HYDROGEN GAS IS PRODUCED
A METAL HYDROXIDE IS FORMED
GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS
THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS

34. REACTION WITH WATER LITHIUM
GROUP I METALS REACT WITH COLD WATER
THE REACTIVITY INCREASES DOWN THE GROUP
HYDROGEN GAS IS PRODUCED
A METAL HYDROXIDE IS FORMED
GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS
THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS
LITHIUM
FLOATS
STEADILY GIVES OFF A GAS
CLEAR ALKALINE SOLUTION LEFT
LITHIUM HYDROXIDE FORMED

35. REACTION WITH WATER SODIUM
GROUP I METALS REACT WITH COLD WATER
THE REACTIVITY INCREASES DOWN THE GROUP
HYDROGEN GAS IS PRODUCED
A METAL HYDROXIDE IS FORMED
GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS
THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS
SODIUM
FLOATS AND MOVES ABOUT
MELTS TO A SPHERE
GIVES OFF A GAS
YELLOW FLAME
CLEAR ALKALINE SOLUTION LEFT
SODIUM HYDROXIDE FORMED
ANIMATION

36. REACTION WITH WATER POTASSIUM
GROUP I METALS REACT WITH COLD WATER
THE REACTIVITY INCREASES DOWN THE GROUP
HYDROGEN GAS IS PRODUCED
A METAL HYDROXIDE IS FORMED
GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS
THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS
POTASSIUM
FLOATS AND MOVES ABOUT
VIGOROUS REACTION
GIVES OFF A GAS
LILAC FLAME
CLEAR ALKALINE SOLUTION LEFT
POTASSIUM HYDROXIDE FORMED
ANIMATION

37. REACTION WITH WATER RUBIDIUM
GROUP I METALS REACT WITH COLD WATER
THE REACTIVITY INCREASES DOWN THE GROUP
HYDROGEN GAS IS PRODUCED
A METAL HYDROXIDE IS FORMED
GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS
THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS
RUBIDIUM
WHAT WOULD YOU EXPECT?

38. REACTION WITH WATER- Equations
Write out the word equation
SODIUM WATER SODIUM HYDROXIDE HYDROGEN

39. REACTION WITH WATER- Equations
Write out the word equation
SODIUM WATER SODIUM HYDROXIDE HYDROGEN
Write out the formulae
Na H2O NaOH H2

40. REACTION WITH WATER- Equations
Write out the word equation
SODIUM WATER SODIUM HYDROXIDE HYDROGEN
Write out the formulae
Na H2O NaOH H2
If the equation doesn’t balance, multiply the formulae until it does

41. REACTION WITH WATER- Equations
Write out the word equation
SODIUM WATER SODIUM HYDROXIDE HYDROGEN
Write out the formulae
Na H2O NaOH H2
If the equation doesn’t balance, multiply the formulae until it does
Na H2O NaOH H2

42. REACTION WITH WATER- Equations
Write out the word equation
SODIUM WATER SODIUM HYDROXIDE HYDROGEN
Write out the formulae
Na H2O NaOH H2
If the equation doesn’t balance, multiply the formulae until it does
Na H2O NaOH H2
Na H2O NaOH H2

43. REACTION WITH WATER- Equations The equation is balanced.
Write out the word equation
SODIUM WATER SODIUM HYDROXIDE HYDROGEN
Write out the formulae
Na H2O NaOH H2
If the equation doesn’t balance, multiply the formulae until it does
Na H2O NaOH H2
Na H2O NaOH H2
2Na H2O NaOH H2
The equation is balanced.

44. REACTION WITH WATER- Equations
2Li H2O LiOH H2
LITHIUM WATER LITHIUM HYDROXIDE HYDROGEN

45. REACTION WITH WATER- Equations
2Li H2O LiOH H2
LITHIUM WATER LITHIUM HYDROXIDE HYDROGEN
2Na H2O NaOH H2
SODIUM WATER SODIUM HYDROXIDE HYDROGEN

46. REACTION WITH WATER- Equations
2Li H2O LiOH H2
LITHIUM WATER LITHIUM HYDROXIDE HYDROGEN
2Na H2O NaOH H2
SODIUM WATER SODIUM HYDROXIDE HYDROGEN
POTASSIUM WATER
RUBIDIUM WATER

47. REACTION WITH WATER- Equations
2Li H2O LiOH H2
LITHIUM WATER LITHIUM HYDROXIDE HYDROGEN
2Na H2O NaOH H2
SODIUM WATER SODIUM HYDROXIDE HYDROGEN
2K H2O KOH H2
POTASSIUM WATER POTASSIUM HYDROXIDE HYDROGEN
2Rb H2O RbOH H2
RUBIDIUM WATER RUBIDIUM HYDROXIDE HYDROGEN

48. REACTION WITH HALOGENS

49. REACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.

50. REACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.
SODIUM CHLORINE SODIUM CHLORIDE +

51. REACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.
SODIUM CHLORINE SODIUM CHLORIDE +
POTASSIUM CHLORINE +

52. REACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.
SODIUM CHLORINE SODIUM CHLORIDE +
POTASSIUM CHLORINE POTASSIUM CHLORIDE +

53. REACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.
SODIUM CHLORINE SODIUM CHLORIDE +
POTASSIUM CHLORINE POTASSIUM CHLORIDE +
SODIUM BROMINE +

54. REACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.
SODIUM CHLORINE SODIUM CHLORIDE +
POTASSIUM CHLORINE POTASSIUM CHLORIDE +
SODIUM BROMINE SODIUM BROMIDE +

55. REACTION WITH HALOGENS - Equations
Na Cl NaCl
SODIUM CHLORINE SODIUM CHLORIDE

56. REACTION WITH HALOGENS - Equations
Na Cl NaCl
SODIUM CHLORINE SODIUM CHLORIDE
The equation doesn’t balance - multiply the formulae until it does

57. REACTION WITH HALOGENS- Equations
Na Cl NaCl
SODIUM CHLORINE SODIUM CHLORIDE
2Na Cl NaCl
SODIUM CHLORINE SODIUM CHLORIDE
The equation is balanced

58. FORMATION OF SODIUM CHLORIDENa Cl
SODIUM ATOM
2,8,1
CHLORINE ATOM
2,8,7
11 protons; 11 electrons
17 protons; 17 electrons
PRESS THE SPACE BAR TO START THE ANIMATION

59. FORMATION OF SODIUM CHLORIDE+ Na Cl
SODIUM ION
2,8
CHLORIDE ION
2,8,8
11 protons; 10 electrons
17 protons; 18 electrons
both species now have ‘full’ outer shells; ie they have the electronic configuration of a noble gas

60. FORMATION OF SODIUM CHLORIDE+ Na Cl
SODIUM ION
2,8
CHLORIDE ION
2,8,8
Na Na e¯
2,8, ,8
ELECTRON TRANSFERRED
Cl e¯ Cl¯
2,8, ,8,8

61. GROUP I - SUMMARY ● ● ● ● Li Na K 2,1 2,8,1 2,8,8,1 181°C 91°C 63°C
LITHIUM
SODIUM
POTASSIUM
SYMBOL Li Na K
ELECTRONIC CONFIGURATION
2,1
2,8,1
● ● ● ●
2,8,8,1
HARDNESS
CAN BE CUT
EASY TO CUT
VERY EASY TO CUT
DENSITY
(Compared to water)
JUST OVER HALF
JUST LIGHTER
A BIT LIGHTER
METHOD OF STORAGE
IN OIL
IN OIL
IN OIL
MELTING POINT
181°C
91°C
63°C
REACTION WITH OXYGEN IN THE AIR
Tarnishes quickly
Tarnishes very quickly
Tarnishes very quickly
FORMULA OF OXIDE
Li20
Na2O
K2O
REACTION WITH WATER
steady
fast
very fast
PRODUCTS
LITHIUM HYDROXIDE & HYDROGEN
SODIUM HYDROXIDE & HYDROGEN
POTASSIUM HYDROXIDE & HYDROGEN

62. QUICK QUIZ ELEMENTS IN GROUP I ARE KNOWN AS THE ………. METALS
WHAT ARE THE NAMES OF THE ELEMENTS?
HOW DOES THE ATOMIC NUMBER CHANGE DOWN THE GROUP?
HOW DOES THE MELTING POINT CHANGE?
HOW DOES THE ATOMIC SIZE (RADIUS) CHANGE?
HOW MANY ELECTRONS DO THEY HAVE IN THE OUTER SHELL?
WHAT TYPE OF ION DO THEY FORM?
HOW DOES THEIR REACTIVITY CHANGE DOWN THE GROUP?
WHAT TYPE OF COMPOUND DO THEY FORM WITH NON-METALS?
DO THEIR HYDROXIDES DISSOLVE IN WATER?
WHAT TYPE OF SOLUTION DO THEIR HYDROXIDES GIVE?
HOW CAN YOU EXPLAIN THEIR RELATIVE REACTIVITY IN TERMS OF THE ATOMIC STRUCTURE?

63. QUICK QUIZ - ANSWERS ALKALI METALS
LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, FRANCIUM
ATOMIC NUMBER INCREASES DOWN THE GROUP
MELTING POINT DECREASES DOWN THE GROUP
ATOMIC SIZE INCREASES DOWN THE GROUP
ALL HAVE ONE ELECTRON IN THE OUTER SHELL (ENERGY LEVEL)
FORM IONS OF CHARGE +1
REACTIVITY INCREASES DOWN THE GROUP
FORM IONIC COMPOUNDS WITH NON-METALS
HYDROXIDES DISSOLVE IN WATER
HYDROXIDES FORM ALKALINE SOLUTIONS
AS THE ATOMS GET BIGGER THE OUTER SHELL ELECTRON IS FURTHER FROM THE NUCLEUS SO IS EASIER TO REMOVE; THE METALS BECOME MORE REACTIVE

64. © 2011 KNOCKHARDY PUBLISHING & JONATHAN HOPTON
GROUP 1
The alkali metals
THE END
© 2011 KNOCKHARDY PUBLISHING & JONATHAN HOPTON