1.37: Understand How Ions are formed by Electron Loss or Gain

ION: Electrically charged atom or a group of atoms that are formed by the Loss or Gain of Electrons

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• Loss or gain of Electrons result in the formation of an ion with full outer shell of Electrons
• Electronic configuration of an ion will be the same as that of a Noble Gas - Such as Helium, Neon and Argon

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IONISATION OF METALS AND NON - METALS:

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• METALS: Loses Electrons to another atom and become Positively Charged Ions
• NON - METALS: Gain Electrons from another atom and become Negatively Charged Ions

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METALS	NON - METALS
Positively Charged Sodium and Aluminium Ions	Negatively Charged Oxide and Chloride Ions

1.38: Know the Charges of these Ions:

CHARGES OF POSITIVE IONS:                                   

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ION	CHARGE
GROUP 1 METALS   ( Li, Na, K, Rb, Cs, Fr )	1+
GROUP 2 METALS   ( Be, Mg, Ca, Sr, Ba, Ra )	2+
GROUP 3 METALS   ( B, Al, Ga, In, TI )	3+
SILVER ( Ag )	Ag+
COPPER ( Cu )	Cu+
IRON II ( Fe )	Fe2+
IRON III ( Fe )	Fe3+
LEAD ( Pb )	Pb4+
ZINC ( Zn )	Zn2+
HYDROGEN ( H )	H+
AMMONIUM ( NH4 )	NH4+

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CHARGES OF NEGATIVE IONS:                                   

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ION	CHARGE
GROUP 5 NON - METALS   ( N, P, As )	3-
GROUP 6 NON - METALS   ( O, S, Se, Te )	2-
GROUP 7 NON - METALS   ( F, Cl, Br, I, At )	1-
HYDROXIDE ( OH )	OH-
CARBONATE ( CO3 )	CO32-
NITRATE ( NO3 )	NO3-
SULFATE ( SO4 )	SO42-

1.39: Write Formulae for Compounds Formed Between the Ions Listed Above

IONIC COMPOUNDS: Formed when Atoms of Metals transfer Electrons to atoms of Non - Metals to form Compounds made up of ions

FORMULAE FOR COMPOUNDS FORMED BETWEEN IONS

• METALS: Loses Electrons to another atom and become Positively Charged Ions
• NON - METALS: Gains Electrons from another atom to become Negatively Charged Ions

Example 1:

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Sodium Chloride, NaCl (typical Ionic Bond)

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SODIUM ATOM Sodium is a Group 1 Metal so will need to lose one outer Electron to another Atom to have a full outer shell of Electrons They will lose an Electron to form a Positive ion with the Charge 1+ (as they lose one outer electron)           Na   2 . 8 . 1      →      Na+   2 . 8 CHLORINE ATOM Chlorine is a Group 7 Non-Metal so will need to gain an Electron to have a full outer shell of Electrons One Electron will be transferred from the outer shell of the Sodium atom to the outer shell of the Chlorine atom Chlorine atom will gain an Electron to form a Negative ion with Charge 1- (as they gain an outer electron)           Cl   2 . 8 . 7      →      Cl-   2 . 8 . 8 FORMULAE OF IONIC COMPOUND:    NaCl

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Example 2:

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Magnesium Oxide, MgO (typical Ionic Bond)

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MAGNESIUM ATOM Magnesium is a Group 2 Metal so will need to lose two outer Electrons to another atom to have a full outer shell of Electrons They will lose two Electrons to form a Positive Ion with the Charge 2+ (as they lose two outer electrons)           Mg   2 . 8 . 2      →      Mg2+   2 . 8 OXYGEN ATOM Oxygen is a Group 6 Non-Metal so will need to gain two Electrons to have a full outer shell of Electrons Two Electrons will be transferred from the outer shell of the Magnesium atom to the outer shell of the Oxygen atom Oxygen atom will gain two Electrons to form a Negative ion with Charge 2- (as they gain two outer electrons)           O2   2 . 8 . 6      →      O22-   2 . 8 . 8 FORMULAE OF IONIC COMPOUND:    MgO

1.40: Draw Dot-and-Cross Diagrams to Show the Formation of Ionic Compounds by Electron Transfer, Limited to Combinations of Elements from Groups 1, 2, 3 and 5, 6, 7

IONIC COMPOUNDS: Formed when atoms of Metals transfer Electrons to atoms of Non-Metals to form Compounds made up of ions

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DOT-AND-CROSS DIAGRAMS: Shows the ionic bonds between ions formed from the loss and gain of Electrons

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• Only the outer shell of Electrons are drawn
• Electrons in one atom will be represented as Crosses, whilst Electrons in other atom will be represented as circles to indicate which ion loses or gains Electrons
• Charges of each ion is displayed on the upper right corner of each ion

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Example 1:

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Sodium Chloride, NaCl (typical ionic bond)

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Diagram showing the Dot-and-Cross Diagram of Magnesium Oxide

EXPLANATION Sodium is a Group 1 Metal so will lose one outer Electron to another atom to have a full outer shell of Electrons They will lose an Electron to form a Positive ion with the Charge 1+ Chlorine is a Group 7 Non-Metal so will gain an Electron to have a full outer shell of Electrons One Electron will be transferred from the outer shell of the Sodium atom to the outer shell of the Chlorine atom Chlorine atom will gain an Electron to form a Negative ion with Charge 1-           FORMULAE OF IONIC COMPOUND:    NaCl

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Example 2:

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Magnesium Oxide, MgO, is a Typical Ionic Bond

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Diagram Showing the Dot-and-Cross Diagram of Magnesium Oxide

EXPLANATION Magnesium is a Group 2 Metal so will lose two outer Electrons to another atom to have a full outer shell of Electrons They will lose two Electrons to form a Positive ion with the Charge 2+ Oxygen is a Group 6 Non - Metal so will gain two Electrons to have a full outer shell of Electrons Two Electrons will be transferred from the outer shell of the Magnesium atom to the outer shell of the Oxygen atom Oxygen atom will gain two Electrons to form a Negative ion with Charge 2-           FORMULAE OF IONIC COMPOUND:    MgO

1.41: Understand Ionic Bonding in Terms of Electrostatic Attractions

IONIC BONDING: Bond between Metal and Non-Metal that has strong electrostatic forces of attraction between the oppositely charged Ions

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Example of an Ionic Bond:

      

Ionic Bonding in Sodium Chloride ( NaCl )

1.42: Understand Why Compounds with Giant Ionic Lattices have High Melting and Boiling Points

GIANT IONIC LATTICE: Giant three dimensional lattice structure held together by the strong attraction between oppositely charged ions

Example:

Diagram showing the Lattice Structure of Sodium Chloride

MELTING AND BOILING POINT OF COMPOUNDS WITH GIANT IONIC LATTICES:

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• Giant ionic lattices are held together by the strong attraction between oppositely charged ions with many of these ions and bonds in structure
• Large amounts of heat energy is therefore needed to overcome these forces of attraction and break down the bonds

1.43: Know that Ionic Compounds Do Not Conduct Electricity when Solid, But Do Conduct Electricity When Molten and in Aqueous Solution

IONIC COMPOUNDS: Formed when atoms of Metals transfer Electrons to atoms of Non-Metals to form Compounds made up of ions

                                     Diagram showing Particles of Ionic Compounds in Solids

                                     and when in Molten / Solution Form

ELECTRICAL CONDUCTIVITY OF IONIC COMPOUNDS:

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• Ionic Compounds cannot conduct electricity when in solid state as ions are fixed in structure and are not free to move
• However, Ionic Compounds can conduct electricity when Molten or in Aqueous Solution as their ions are free to move to conduct an electric charge