Post on 15-Dec-2015
GROUP 1GROUP 1The alkali metalsThe alkali metals
National 5 ChemistryNational 5 Chemistry
KNOCKHARDY PUBLISHINGKNOCKHARDY PUBLISHING
GROUP IGROUP I
INTRODUCTION
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All diagrams and animations in this Powerpoint are original and created by Jonathan Hopton. Permission must be obtained for their use in any commercial work.
CONTENTSCONTENTS
• Introduction
• Group trends
• Group similarities
• Flame tests
• Reaction with water
• Reaction with halogens
• Summary
• Quick quiz
GROUP IGROUP I
INTRODUCTIONINTRODUCTION
INTRODUCTIONINTRODUCTION
THE ALKALI METALS ARE IN GROUP I OF THE PERIODIC TABLE
Group 1 2 3 4 5 6 7
0
Li
Na
K
Rb
Fr
Cs
INTRODUCTIONINTRODUCTION
THE ALKALI METALS ARE IN GROUP I OF THE PERIODIC TABLE
Group 1 2 3 4 5 6 7
0
Li
Na
K
Rb
Fr
THEY ARE VERY REACTIVE METALS AND HAVE ELECTRONIC CONFIGURATIONS WITH ONE ELECTRON IN THE OUTER SHELL
Cs
GROUP PROPERTIESGROUP PROPERTIES
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
GROUP PROPERTIESGROUP PROPERTIES
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
GROUP TRENDSGROUP TRENDS
GROUP TRENDSGROUP TRENDS
APPEARANCEAPPEARANCE
Density / gcm-3
Li Na K Rb
0.53 0.97 0.86 1.53
Cs
1.87
Appearance Grey solid Grey solid Grey solid Grey solid Grey solid
Flame test Crimson Yellow Lilac Red-violet Blue-violet
GROUP TRENDSGROUP TRENDS
DECREASES down Group as the atoms get larger
APPEARANCEAPPEARANCE
MELTING POINTMELTING POINT
Melting point / °C
Li Na K Rb
180.7 98 63.8 39.2
Cs
43.2
Density / gcm-3
Li Na K Rb
0.53 0.97 0.86 1.53
Cs
1.87
Appearance Grey solid Grey solid Grey solid Grey solid Grey solid
Flame test Crimson Yellow Lilac Red-violet Blue-violet
GROUP TRENDSGROUP TRENDS
Configuration
ELECTRONIC CONFIGURATIONELECTRONIC CONFIGURATION
Atomic Number
Li Na K Rb
3 11 19 37
Cs
55
2,1 2,8,1 2,8,8,1 2,8,18,8,1 2,8,18,18,8,1
GROUP TRENDSGROUP TRENDS
• electrons go into shells further from the nucleus
Configuration
ELECTRONIC CONFIGURATIONELECTRONIC CONFIGURATION
Atomic Number
Li Na K Rb
3 11 19 37
Cs
55
2,1 2,8,1 2,8,8,1 2,8,18,8,1 2,8,18,18,8,1
11+3+ 19+
LITHIUM2,1
SODIUM2,8,1
POTASSIUM2,8,8,1
GROUP TRENDSGROUP TRENDS
Li Na K Rb
ATOMIC RADIUSATOMIC RADIUS
0.152 0.185 0.227 0.247Atomic radius / nm
Cs
0.265
LiRbNa K Cs
GROUP TRENDSGROUP TRENDS
ATOMIC RADIUS INCREASES down Group
• the greater the atomic number the more electrons there are; these go into shells increasingly further from the nucleus
Li Na K Rb
ATOMIC RADIUSATOMIC RADIUS
0.152 0.185 0.227 0.247Atomic radius / nm
Cs
0.265
LiRbNa K Cs
GROUP TRENDSGROUP TRENDS
ATOMIC & IONIC RADIUSATOMIC & IONIC RADIUS
Li Na K Rb
0.152 0.185 0.227 0.247Atomic radius / nm
Cs
0.265
LiRbNa K Cs
Li+ Na+ K+ Rb+
0.068 0.098 0.133 0.148Ionic radius / nm
Cs+
0.167
Li+
Rb+Na+K+
Cs+
IONIC RADIUS INCREASES down Group
• ions are smaller than atoms - the removal of an electron means that there are now fewer shells
GROUP GROUP SIMILARITIESSIMILARITIES
GROUP GROUP SIMILARITIESSIMILARITIES
ION FORMATIONION FORMATION
Configuration
Ion
Li Na K Rb
Li+ Na+ K+ Rb+
Cs
Cs+
2 2,8 2,8,8 2,8,18,8 2,8,18,18,8
GROUP GROUP SIMILARITIESSIMILARITIES
ION FORMATIONION FORMATION
• 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
Configuration
Ion
Li Na K Rb
Li+ Na+ K+ Rb+
Cs
Cs+
2 2,8 2,8,8 2,8,18,8 2,8,18,18,8
GROUP GROUP SIMILARITIESSIMILARITIES
ION FORMATIONION FORMATION
• 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
Configuration
Ion
Li Na K Rb
Li+ Na+ K+ Rb+
Cs
Cs+
2 2,8 2,8,8 2,8,18,8 2,8,18,18,8
11+ 11+SODIUM ATOM11 PROTONS
11 ELECTRONS
SODIUM ION11 PROTONS
10 ELECTRONS
GROUP GROUP SIMILARITIESSIMILARITIES
ION FORMATIONION FORMATION
• 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 increases down the Group as atoms get larger
Increasingly reactive
Configuration
Ion
Li Na K Rb
Li+ Na+ K+ Rb+
Cs
Cs+
2 2,8 2,8,8 2,8,18,8 2,8,18,18,8
Li Na K Rb Cs
REACTIVITYREACTIVITY
FLAME TESTSFLAME TESTS
FLAME TESTSFLAME 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
FLAME TESTSFLAME 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 CaNORMALBUNSEN
BLUE- BRIGHT APPLE LILAC BRICKGREEN YELLOW GREEN RED
FLAME TESTSFLAME 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
FLAME TESTSFLAME TESTS
CONTINUOUS SPECTRUM
• A LINE SPECTRUM IS PRODUCED
• 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
FLAME TESTSFLAME TESTS
CONTINUOUS SPECTRUM
LINE SPECTRUM
• A LINE SPECTRUM IS PRODUCED
• 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
FLAME TESTSFLAME TESTS
CONTINUOUS SPECTRUM
LINE SPECTRUM
EACH METAL HAS ITS OWN CHARACTERISTIC LINE SPECTRUM
• A LINE SPECTRUM IS PRODUCED
• 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
REACTIONS OF ALKALI METALSREACTIONS 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.
REACTIONS OF ALKALI METALSREACTIONS 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.
LITHIUM2,1
11+
3+
SODIUM2,8,1
19+
POTASSIUM2,8,8,1
REACTIONS OF ALKALI METALSREACTIONS OF ALKALI METALS
GETS INCREASINGLY EASIER TO REMOVE THE OUTER SHELL ELECTRON
REACTION WITH WATERREACTION WITH WATER
REACTION WITH WATERREACTION WITH WATER
1. GROUP I METALS REACT WITH COLD WATER
2. THE REACTIVITY INCREASES DOWN THE GROUP
3. HYDROGEN GAS IS PRODUCED
4. A METAL HYDROXIDE IS FORMED
5. GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS
6. THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS
REACTION WITH WATERREACTION WITH WATER
1. GROUP I METALS REACT WITH COLD WATER
2. THE REACTIVITY INCREASES DOWN THE GROUP
3. HYDROGEN GAS IS PRODUCED
4. A METAL HYDROXIDE IS FORMED
5. GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS
6. THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS
LITHIUM
FLOATS
STEADILY GIVES OFF A GAS
CLEAR ALKALINE SOLUTION LEFT
LITHIUM HYDROXIDE FORMED
REACTION WITH WATERREACTION WITH WATER
1. GROUP I METALS REACT WITH COLD WATER
2. THE REACTIVITY INCREASES DOWN THE GROUP
3. HYDROGEN GAS IS PRODUCED
4. A METAL HYDROXIDE IS FORMED
5. GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS
6. 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 FORMEDANIMATION
REACTION WITH WATERREACTION WITH WATER
1. GROUP I METALS REACT WITH COLD WATER
2. THE REACTIVITY INCREASES DOWN THE GROUP
3. HYDROGEN GAS IS PRODUCED
4. A METAL HYDROXIDE IS FORMED
5. GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS
6. 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 FORMEDANIMATION
REACTION WITH WATERREACTION WITH WATER
1. GROUP I METALS REACT WITH COLD WATER
2. THE REACTIVITY INCREASES DOWN THE GROUP
3. HYDROGEN GAS IS PRODUCED
4. A METAL HYDROXIDE IS FORMED
5. GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS
6. THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS
RUBIDIUM
WHAT WOULD YOU EXPECT?
REACTION WITH WATER- EquationsREACTION WITH WATER- Equations
SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN
Write out the word equation
Na + H2O NaOH + H2
SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN
Write out the word equation
Write out the formulae
REACTION WITH WATER- EquationsREACTION WITH WATER- Equations
Na + H2O NaOH + H2
SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN
Write out the word equation
Write out the formulae
If the equation doesn’t balance, multiply the formulae until it does
REACTION WITH WATER- EquationsREACTION WITH WATER- Equations
Na + H2O NaOH + H2
SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN
Write out the word equation
Write out the formulae
Na + 2H2O NaOH + H2
If the equation doesn’t balance, multiply the formulae until it does
REACTION WITH WATER- EquationsREACTION WITH WATER- Equations
Na + H2O NaOH + H2
SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN
Write out the word equation
Na + 2H2O 2NaOH + H2
Write out the formulae
Na + 2H2O NaOH + H2
If the equation doesn’t balance, multiply the formulae until it does
REACTION WITH WATER- EquationsREACTION WITH WATER- Equations
Na + H2O NaOH + H2
SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN
Write out the word equation
Na + 2H2O 2NaOH + H2
Write out the formulae
Na + 2H2O NaOH + H2
If the equation doesn’t balance, multiply the formulae until it does
2Na + 2H2O 2NaOH + H2
The equation is balanced.
REACTION WITH WATER- EquationsREACTION WITH WATER- Equations
LITHIUM + WATER LITHIUM HYDROXIDE + HYDROGEN
2Li + 2H2O 2LiOH + H2
REACTION WITH WATER- EquationsREACTION WITH WATER- Equations
2Li + 2H2O 2LiOH + H2
2Na + 2H2O 2NaOH + H2
LITHIUM + WATER LITHIUM HYDROXIDE + HYDROGEN
SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN
REACTION WITH WATER- EquationsREACTION WITH WATER- Equations
2Li + 2H2O 2LiOH + H2
2Na + 2H2O 2NaOH + H2
POTASSIUM + WATER
RUBIDIUM + WATER
LITHIUM + WATER LITHIUM HYDROXIDE + HYDROGEN
SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN
REACTION WITH WATER- EquationsREACTION WITH WATER- Equations
2Li + 2H2O 2LiOH + H2
2Na + 2H2O 2NaOH + H2
POTASSIUM + WATER POTASSIUM HYDROXIDE +
HYDROGEN
2K + 2H2O 2KOH + H2
RUBIDIUM + WATER RUBIDIUM HYDROXIDE +
HYDROGEN
2Rb + 2H2O 2RbOH + H2
LITHIUM + WATER LITHIUM HYDROXIDE + HYDROGEN
SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN
REACTION WITH WATER- EquationsREACTION WITH WATER- Equations
REACTION WITH HALOGENSREACTION WITH HALOGENS
REACTION WITH HALOGENSREACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.
REACTION WITH HALOGENSREACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.
SODIUM CHLORINE SODIUM CHLORIDE+
REACTION WITH HALOGENSREACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.
SODIUM CHLORINE SODIUM CHLORIDE+
POTASSIUM CHLORINE +
REACTION WITH HALOGENSREACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.
SODIUM CHLORINE SODIUM CHLORIDE+
POTASSIUM CHLORINE POTASSIUM CHLORIDE+
REACTION WITH HALOGENSREACTION WITH HALOGENS
ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.
SODIUM CHLORINE SODIUM CHLORIDE+
POTASSIUM CHLORINE POTASSIUM CHLORIDE+
SODIUM BROMINE+
REACTION WITH HALOGENSREACTION 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+
REACTION WITH HALOGENS - EquationsREACTION WITH HALOGENS - Equations
Na + Cl2 NaCl
SODIUM CHLORINE SODIUM CHLORIDE
REACTION WITH HALOGENS - EquationsREACTION WITH HALOGENS - Equations
Na + Cl2 NaCl
The equation doesn’t balance - multiply the formulae until it doesThe equation doesn’t balance - multiply the formulae until it does
SODIUM CHLORINE SODIUM CHLORIDE
REACTION WITH HALOGENS- EquationsREACTION WITH HALOGENS- Equations
2Na + Cl2 2NaCl
Na + Cl2 NaCl
SODIUM CHLORINE SODIUM CHLORIDE
SODIUM CHLORINE SODIUM CHLORIDE
The equation is balancedThe equation is balanced
Cl
SODIUM ATOM2,8,1
Na
CHLORINE ATOM2,8,7
11 protons; 11 electrons 17 protons; 17 electrons
FORMATION OF SODIUM CHLORIDEFORMATION OF SODIUM CHLORIDE
PRESS THE SPACE BAR TO START THE ANIMATION
Cl
SODIUM ION2,8
Na
CHLORIDE ION2,8,8
both species now have ‘full’ outer shells; ie they have the electronic configuration of a noble gas
+
11 protons; 10 electrons 17 protons; 18 electrons
FORMATION OF SODIUM CHLORIDEFORMATION OF SODIUM CHLORIDE
Cl
SODIUM ION2,8
Na
CHLORIDE ION2,8,8
Na Na+ + e¯2,8,1 2,8
ELECTRON TRANSFERRED
Cl + e¯ Cl¯2,8,7 2,8,8
+
FORMATION OF SODIUM CHLORIDEFORMATION OF SODIUM CHLORIDE
SYMBOL
ELECTRONIC CONFIGURATION
HARDNESS
DENSITY(Compared to water)
Li
CAN BE CUT
JUST OVER HALF
POTASSIUM
Na
● ● ● ●
LITHIUM SODIUM
K
METHOD OF STORAGE
MELTING POINT
IN OIL
181°C
IN OIL
91°C
IN OIL
63°C
JUST LIGHTER A BIT LIGHTER
REACTION WITH OXYGEN IN THE AIR Tarnishes quickly Tarnishes very quickly Tarnishes very quickly
REACTION WITH WATER steady fast very fast
FORMULA OF OXIDE Li20 Na2O K2O
PRODUCTS LITHIUM HYDROXIDE & HYDROGEN
SODIUM HYDROXIDE & HYDROGEN
POTASSIUM HYDROXIDE & HYDROGEN
EASY TO CUT VERY EASY TO CUT
2,1 2,8,1 2,8,8,1
GROUP I - SUMMARYGROUP I - SUMMARY
QUICK QUIZQUICK QUIZ
1. ELEMENTS IN GROUP I ARE KNOWN AS THE ………. METALS
2. WHAT ARE THE NAMES OF THE ELEMENTS?
3. HOW DOES THE ATOMIC NUMBER CHANGE DOWN THE GROUP?
4. HOW DOES THE MELTING POINT CHANGE?
5. HOW DOES THE ATOMIC SIZE (RADIUS) CHANGE?
6. HOW MANY ELECTRONS DO THEY HAVE IN THE OUTER SHELL?
7. WHAT TYPE OF ION DO THEY FORM?
8. HOW DOES THEIR REACTIVITY CHANGE DOWN THE GROUP?
9. WHAT TYPE OF COMPOUND DO THEY FORM WITH NON-METALS?
10. DO THEIR HYDROXIDES DISSOLVE IN WATER?
11. WHAT TYPE OF SOLUTION DO THEIR HYDROXIDES GIVE?
12. HOW CAN YOU EXPLAIN THEIR RELATIVE REACTIVITY IN TERMS OF THE ATOMIC STRUCTURE?
QUICK QUIZ - ANSWERSQUICK QUIZ - ANSWERS
1. ALKALI METALS
2. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, FRANCIUM
3. ATOMIC NUMBER INCREASES DOWN THE GROUP
4. MELTING POINT DECREASES DOWN THE GROUP
5. ATOMIC SIZE INCREASES DOWN THE GROUP
6. ALL HAVE ONE ELECTRON IN THE OUTER SHELL (ENERGY LEVEL)
7. FORM IONS OF CHARGE +1
8. REACTIVITY INCREASES DOWN THE GROUP
9. FORM IONIC COMPOUNDS WITH NON-METALS
10. HYDROXIDES DISSOLVE IN WATER
11. HYDROXIDES FORM ALKALINE SOLUTIONS
12. AS THE ATOMS GET BIGGER THE OUTER SHELL ELECTRON IS FURTHER FROM THE NUCLEUS SO IS EASIER TO REMOVE; THE METALS BECOME MORE REACTIVE
GROUP 1GROUP 1The alkali metalsThe alkali metals
THE ENDTHE END
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