2.1: Understand How the Similarities in the Reactions of these Elements with Water Provide Evidence for their Recognition as a Family of Elements

ALKALI  METALS: Group 1 Metals that commonly include Lithium, Sodium and  Potassium

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SIMILAR REACTIONS WITH WATER:
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• Group 1 Metals will react similarly with Water as they are a family of Elements called Alkali Metals

• They will react vigorously with Water to produce an Alkaline Metal Hydroxide and Hydrogen Gas

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ELEMENT	REACTION
LITHIUM	Bubbles of gas
SODIUM	Bubbles of gas Melts into a shiny ball that dashes around the surface
POTASSIUM	Bubbles of gas Melts into a shiny ball that dashes around the surface Burns with a lilac-coloured flame

2.2: Understand How the Differences between the Reactions of these Elements with Air and Water Provide Evidence for the Trend in Reactivity in Group 1

ALKALI  METALS: Group 1 Metals that commonly includes Lithium, Sodium and  Potassium

TREND OF REACTIVITY IN GROUP 1 METALS:

• The reactivity of Group 1 Metals will increase down the Group
• The reaction of Group 1 Metals with Air and Water becomes more vigorous as you go down the Group

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REACTION WITH AIR:

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ELEMENT	REACTION
LITHIUM	Burns with a Red flame
SODIUM	Burns with a Yellow / Orange flame
POTASSIUM	Burns with a Lilac-coloured flame

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REACTION WITH WATER:

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ELEMENT	REACTION
LITHIUM	Bubbles of gas
SODIUM	Bubbles of gas Melts into a shiny ball that dashes around the surface
POTASSIUM	Bubbles of gas Melts into a shiny ball that dashes around the surface Burns with a Lilac-coloured flame

2.3: Use Knowledge of Trends in Group 1 to Predict the Properties of Other Alkali Metals

ALKALI  METALS: Group 1 Metals that commonly include Lithium, Sodium and  Potassium

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PROPERTIES OF OTHER ALKALI METALS (RUBIDIUM, CAESIUM AND FRANCIUM):

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• As the reactivity of Alkali Metals increases down the Group, Rubidium, Caesium and Francium will react more vigorously with Air and Water
• Lithium is at the top so will be the least reactive, while Francium is at the bottom so will be the most reactive (Francium is rare and radioactive so is difficult to confirm predict reaction)

PREDICTED REACTION WITH WATER:

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ELEMENT	REACTION
RUBIDIUM	Explodes with sparks
CAESIUM	Violent explosion due to rapid production of heat and Hydrogen
FRANCIUM	*Too Reactive*

2.4C: Explain the Trend in Reactivity in Group 1 in Terms of Electronic Configurations

ALKALI  METALS: Group 1 Metals that commonly Include Lithium, Sodium and Potassium

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ELECTRONIC CONFIGURATION OF THE FIRST THREE ELEMENTS IN GROUP 1:

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TREND IN REACTIVITY OF GROUP 1:
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• Reactivity of Group 1 Metals increases as you go down the Group
• As each Element has only one Electron on their outer shell, they will react to lose one outer electron to form full outer shell of electrons
• As you go down Group 1, the number of shells of Electrons increases (period number increases down the periodic table), hence there are weaker electrostatic forces of attraction as the outer electron is further away from the Nucleus
• Less energy is needed to overcome the electrostatic forces of attraction between the Negatively Charged Electron and the Positively Charged Nucleus
• As Electrons can therefore be lost more easily, the reactivity of Group 1 Metals increases as you go down the Group

2.5: Know the Colours, Physical States (At Room Temperature) and Trends in Physical Properties of these Elements

HALOGENS: Group 7 Non-Metals that are poisonous and commonly include Chlorine, Bromine and Iodine

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COLOURS AND STATES AT ROOM TEMPERATURE:

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HALOGEN	PHYSICAL STATE AT ROOM TEMPERATURE	COLOUR
CHLORINE	Gas	Pale Green
BROMINE	Liquid	Red-Brown (readily evaporates to form a Brown Gas)
IODINE	Solid	Black (sublimes to form a Purple Gas)

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TRENDS IN PHYSICAL PROPERTIES:

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1. MELTING POINT

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• Melting and Boiling Points of Halogens increases as you go down the Group

        

Melting and Boiling Points of Halogens

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2. STATE AT ROOM TEMPERATURE

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• At room temperature (20C℃), the physical state of Halogens become harder and more set as you go down the Group
• Chlorine is a Gas, Bromine is a Liquid and Iodine is a Solid

States of Halogens

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3. COLOUR

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• Halogens become darker as you go down the Group
• Chlorine is Pale Green, Bromine is Red-Brown and Iodine is Black

Colours of Halogens

2.6: Use Knowledge of Trends in Group 7 to Predict the Properties of Other Halogens

HALOGENS: Group 7 Non-Metals that are poisonous and commonly includes Chlorine, Bromine and Iodine

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PROPERTIES OF OTHER HALOGENS (FLUORINE AND ASTATINE):

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1. MELTING AND BOILING POINT

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• Melting and Boiling Point of Halogens increases as you go down the Group
• Fluorine is at the top of Group 7 so will have the lowest melting and boiling point
• Astatine is at the bottom of Group 7 so will have the highest melting and boiling point

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2. STATES

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• State of Halogens become harder and more set as you go down the Group
• Fluorine is at top of Group 7 so will be a Gas
• Astatine is at the bottom of Group 7 so will be a Solid

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3. COLOUR

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• Colour of Halogens become darker as you go down the Group
• Fluorine is at the top of Group 7 so will be lighter coloured : Yellow
• Astatine is at the bottom of Group 7 so will be darker coloured : Black

2.7: Understand How Displacement Reactions involving Halogens and Halides Provide Evidence for the Trend in Reactivity in Group 7

HALOGENS: Group 7 Non-Metals that are poisonous and commonly includes Chlorine, Bromine and Iodine

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DISPLACEMENT REACTIONS

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DISPLACEMENT REACTION: When a more reactive Halogen displaces a less reactive Halogen for an Aqueous Solution of its Halide

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• Reactivity of Group 7 Non-Metals increases as you go up the Group
• Out of the 3 Halogens - Chlorine, Bromine and Iodine - Chlorine is the most reactive and iodine is the least reactive

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AQUEOUS SOLUTION COLOUR OF HALOGENS:

AQUEOUS SOLUTION	COLOUR
CHLORINE	Very pale green, but usually appears colourless as it is dilute
BROMINE	Orange but will turn yellow when diluted
IODINE	Brown

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Examples:

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Chlorine is above Bromine in Group 7 so is more reactive. Chlorine will therefore displace Bromine from an Aqueous Solution of Metal Bromide:

Chlorine  +  Potassium Bromide Solution  →  Potassium Chloride Solution  +  Bromine

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Chlorine is also above Iodine in Group 7 so is more reactive. Chlorine will therefore displace Iodine from an Aqueous Solution of Metal Iodide:

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Chlorine  +  Sodium Iodide Solution  →  Sodium Chloride Solution  +  Iodine

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Bromine is above Iodine in Group 7 so is more reactive. Bromine will therefore displace Iodine from an Aqueous Solution of Metal Iodide:

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Bromine  +  Magnesium Iodide Solution  →  Magnesium Bromide Solution  +  Iodine

2.8C: Explain the Trend in Reactivity in Group 7 in Terms of Electronic Configurations

HALOGENS: Group 7 Non-Metals that are poisonous and commonly includes Chlorine, Bromine and Iodine

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ELECTRONIC CONFIGURATION OF ELEMENTS IN GROUP 7:

TREND IN REACTIVITY OF GROUP 7:
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• Reactivity of Group 7 Non-Metals increases as you go up the Group
• As each Element has seven Electrons on their outer shell, they will react to gain one outer Electron to form full outer shell of electrons
• As you go up Group 7, the number of shells of Electrons decreases (period number decreases up the periodic table), hence there are stronger electrostatic forces of attraction to attract the extra Electron needed as outer Electrons are closer to the Nucleus
• As Electrons can be attracted more readily, the reactivity of Group 7 Non-Metals increases as you go up the Group

2.9: Know the Approximate Percentages by Volume of the Four Most Abundant Gases in Dry Air

THE COMPOSITION OF AIR:

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Table below shows the approximate percentage by volume of the main gases in unpolluted, dry Air:

GAS	PERCENTAGE IN AIR
NITROGEN	78 %
OXYGEN	21 %
ARGON	0.9 %
CARBON DIOXIDE	0.04 %