What is a crystalline lattice ?

A crystalline lattice is a solid structure in which ions, atoms or molecules are arranged in a regular and repeating three-dimensional pattern.

An ionic bond is an electrostatic force of attraction between a positively charged metal cation and a negatively charged non-metal anion.

Why do ionic compounds have high melting points?

Ionic compounds have high melting points because strong electrostatic forces of attraction between oppositely charged ions in the ionic lattice require high temperatures to overcome. Compounds with ions of greater charge have even higher melting points.

Why can ionic compounds conduct electricity when molten or in solution, but not in the solid state?

In the molten state or in solution , ions are free to move and carry charge. In the solid state, ions are in fixed positions within the lattice and cannot move.

True or False? Ionic compounds cannot conduct electricity in any state.

False. Ionic compounds can conduct electricity when molten or in solution , because ions are free to move. They cannot conduct in the solid state.

Why do many ionic compounds dissolve in polar solvents?

Polar molecules such as water can disrupt the ionic lattice , surrounding each ion: the δ+ end attracts anions and the δ− end attracts cations. Solubility depends on the relative strength of lattice forces versus ion-dipole attractions.

In general, the greater the ionic charge , the .......... soluble an ionic compound is.

In general, the greater the ionic charge , the less soluble an ionic compound is.

How does electrolysis provide evidence for the existence of ions?

During electrolysis, positive ions migrate to the negative electrode and negative ions migrate to the positive electrode . This directed movement of charged particles confirms that ionic compounds contain ions.

What is observed during electrolysis of copper(II) chromate(VI) solution, and what does this show?

A blue colour appears at the negative electrode (Cu 2+ ions migrating) and a yellow colour at the positive electrode (CrO 4 2- ions migrating). This colour separation provides direct visual evidence for the existence and movement of ions.

A cation is a positively charged ion formed when a metal atom loses one or more electrons from its valence shell.

An anion is a negatively charged ion formed when a non-metal atom gains one or more electrons into its outer shell.

In ionic bonding, what do metal atoms and non-metal atoms each do?

Metal atoms lose electrons from their valence shell to form positively charged cations . Non-metal atoms gain electrons to form negatively charged anions . Both end up with a full outer shell matching a noble gas configuration.

True or False? An ionic bond is a directional bond.

False. An ionic bond is non-directional : the electrostatic attraction between oppositely charged ions acts in all directions, so each ion attracts all surrounding ions of opposite charge.

What is an ionic bond?

An ionic bond is the strong electrostatic attraction between oppositely charged ions. It acts in all directions, making it non-directional, and requires a large amount of energy to overcome.

Why is an ionic lattice overall electrically neutral?

Ions are arranged in a regular repeating pattern in which positive charges cancel out negative charges. Each ion is attracted to all surrounding oppositely charged ions so the lattice as a whole carries no net charge.

When atoms form ions through ionic bonding, they achieve the electronic configuration of a .......... gas.

When atoms form ions through ionic bonding, they achieve the electronic configuration of a noble gas.

Why are 2 fluoride ions needed for every calcium ion in calcium fluoride (CaF 2 )?

Calcium forms a Ca 2+ ion by losing 2 electrons. Each fluorine atom can only accept 1 electron, forming an F - ion. Two F - ions are needed to cancel the 2+ charge of the Ca 2+ ion, making the overall compound neutral.

What are the conventions for drawing an ionic dot-and-cross diagram?

Only outer-shell electrons are shown, represented as dots and crosses. Brackets are drawn around each ion to show that the charge is spread evenly, and the ionic charge is written at the top right-hand corner of each bracket.

Atomic radius is the distance between the nucleus and the outermost electron of an atom. It is measured by halving the distance between the nuclei of two bonded atoms of the same element.

Why does atomic radius decrease across a period?

Across a period, nuclear charge increases as more protons are added, but the number of electron shells stays the same so shielding is constant. The greater nuclear charge pulls the outer electrons closer to the nucleus, reducing the atomic radius .

True or False? Shielding increases across a period in the periodic table.

False. Elements across a period all have the same number of electron shells, so the shielding effect remains constant. It is the increasing nuclear charge that causes atomic radius to decrease.

Ionic radius is a measure of the size of an ion. It increases with greater negative charge (more electrons gained) and decreases with greater positive charge (electrons lost, same nuclear charge).

Why is a negative ion larger than its parent atom?

Gaining electrons increases the number of electrons around the same nucleus. The nuclear charge is unchanged, so the electrostatic pull on each electron is weaker, allowing the electron cloud to expand and increasing the ionic radius .

What factors determine the strength of an ionic bond?

Ionic bond strength depends on the charge and size of the ions. Higher ionic charges and smaller ionic radii produce a greater charge density and therefore stronger ionic bonds.

Ions with the same electronic configuration but different numbers of protons are called .......... ions.

Ions with the same electronic configuration but different numbers of protons are called isoelectronic ions.

How does ionic radius change across a series of isoelectronic ions such as N 3- , O 2- , F - , Na + , Mg 2+ , Al 3+ ?

The ionic radius decreases across this series. All ions have the same electronic configuration, but the number of protons increases. The greater nuclear charge pulls the electrons more strongly inward, reducing the ionic radius.

True or False? The ionic radius of a positive ion increases as the positive charge increases.

False. Ionic radius decreases with increasing positive charge. Losing more electrons leaves fewer electrons subject to the same nuclear charge, so the electrostatic attraction per electron is stronger and the ion is smaller.

Define polarisation (of an anion)

Polarisation is the distortion of the electron density of an anion caused by the electric field of a nearby cation, introducing covalent character into an otherwise ionic bond.

Define polarising power

Polarising power is the ability of a cation to distort (polarise) a nearby anion. It is greater for cations with a high charge density, meaning those that are small and highly charged.

What factors give a cation high polarising power?

A cation has high polarising power when it is small and highly charged . Both features increase the charge density of the cation, allowing it to exert a stronger pull on the electron cloud of a nearby anion.

What makes an anion highly polarisable?

An anion is more easily polarised when it has a large ionic radius . Outer electrons are further from the nucleus and held less tightly, so they are more easily distorted by the electric field of a nearby cation.

True or False? A larger cation has greater polarising power than a smaller cation of the same charge.

False. A larger cation has lower polarising power. Its lower charge density means it exerts a weaker pull on the electron cloud of a nearby anion. For example, K + has lower polarising power than Li + .

When an anion is polarised by a cation, .......... character is introduced into the bond.

When an anion is polarised by a cation, covalent character is introduced into the bond.

Why can the theoretical lattice energy of an ionic compound differ from the experimentally measured value?

The theoretical model assumes perfect spherical ions with purely electrostatic interactions. In reality, polarisation of the anion by the cation introduces covalent character , causing the measured lattice energy to differ from the theoretical prediction.

Why does Mg 2+ have a greater polarising power than Na + ?

Mg 2+ has a greater charge than Na + and a similar (or smaller) ionic radius, giving it a higher charge density . The stronger electric field of Mg 2+ distorts a nearby anion more effectively.

A metallic bond is the strong electrostatic force of attraction between positively charged metal ions and the surrounding sea of delocalised electrons in a giant metallic lattice.

What are delocalised electrons in a metal?

Delocalised electrons are outer-shell electrons that are not bound to any individual metal atom. They move freely throughout the metallic lattice, forming a 'sea' of electrons that holds the positive metal ions together.

Why do metals conduct electricity?

Metals conduct electricity because delocalised electrons are free to move and carry charge through the lattice. When a potential difference is applied, electrons enter one end and displace others at the far end, allowing current to flow.

Why are metals malleable and ductile?

Layers of positive metal ions can slide over one another into new positions. The delocalised electrons move with the layers, maintaining the electrostatic forces without breaking the metallic bonds.

True or False? Metals have low melting points because metallic bonds are weak.

False. Metallic bonds are strong electrostatic forces between delocalised electrons and positive metal ions. They require large amounts of energy to overcome, so metals generally have high melting points .

When other atoms, such as carbon atoms, are added to a pure metal structure, the resulting mixture is called an .......... .

When other atoms, such as carbon atoms, are added to a pure metal structure, the resulting mixture is called an alloy .

What three factors increase the strength of a metallic bond?

Increasing the number of delocalised electrons per metal atom Increasing the positive charge on the metal ions Decreasing the size of the metal ions

Why are alloys stronger than pure metals?

In an alloy, atoms of different sizes are present. These disrupt the regular layers of metal ions, preventing the layers from sliding over each other easily and making the structure harder and stronger.

True or False? Metals conduct heat only through the vibration of positive ions in the lattice.

False. Heat conduction in metals involves both vibration of positive ions and the movement of delocalised electrons . Electrons convert kinetic energy to heat when they collide with metal atoms, transferring energy through the structure.

International A Level (IAL)ChemistryEdexcelFlashcards1. Structure, Bonding & Introduction to Organic ChemistryIonic & Metallic Bonding & Structure

Ionic & Metallic Bonding & Structure (Edexcel International A Level (IAL) Chemistry): Flashcards

Exam code: YCH11

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FrontEvidence of Ions
What is a crystalline lattice?

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Cards in this collection (44)

What is a crystalline lattice?
A crystalline lattice is a solid structure in which ions, atoms or molecules are arranged in a regular and repeating three-dimensional pattern.
Define ionic bond
An ionic bond is an electrostatic force of attraction between a positively charged metal cation and a negatively charged non-metal anion.
Why do ionic compounds have high melting points?
Ionic compounds have high melting points because strong electrostatic forces of attraction between oppositely charged ions in the ionic lattice require high temperatures to overcome. Compounds with ions of greater charge have even higher melting points.
Why can ionic compounds conduct electricity when molten or in solution, but not in the solid state?
In the molten state or in solution, ions are free to move and carry charge. In the solid state, ions are in fixed positions within the lattice and cannot move.
True or False?
Ionic compounds cannot conduct electricity in any state.
False.
Ionic compounds can conduct electricity when molten or in solution, because ions are free to move. They cannot conduct in the solid state.
Why do many ionic compounds dissolve in polar solvents?
Polar molecules such as water can disrupt the ionic lattice, surrounding each ion: the δ+ end attracts anions and the δ− end attracts cations. Solubility depends on the relative strength of lattice forces versus ion-dipole attractions.
In general, the greater the ionic charge, the .......... soluble an ionic compound is.
In general, the greater the ionic charge, the less soluble an ionic compound is.
How does electrolysis provide evidence for the existence of ions?
During electrolysis, positive ions migrate to the negative electrode and negative ions migrate to the positive electrode. This directed movement of charged particles confirms that ionic compounds contain ions.
What is observed during electrolysis of copper(II) chromate(VI) solution, and what does this show?
A blue colour appears at the negative electrode (Cu²⁺ ions migrating) and a yellow colour at the positive electrode (CrO₄^2- ions migrating). This colour separation provides direct visual evidence for the existence and movement of ions.
Define cation
A cation is a positively charged ion formed when a metal atom loses one or more electrons from its valence shell.
Define anion
An anion is a negatively charged ion formed when a non-metal atom gains one or more electrons into its outer shell.
In ionic bonding, what do metal atoms and non-metal atoms each do?
Metal atoms lose electrons from their valence shell to form positively charged cations. Non-metal atoms gain electrons to form negatively charged anions. Both end up with a full outer shell matching a noble gas configuration.
True or False?
An ionic bond is a directional bond.
False.
An ionic bond is non-directional: the electrostatic attraction between oppositely charged ions acts in all directions, so each ion attracts all surrounding ions of opposite charge.
What is an ionic bond?
An ionic bond is the strong electrostatic attraction between oppositely charged ions. It acts in all directions, making it non-directional, and requires a large amount of energy to overcome.
Why is an ionic lattice overall electrically neutral?
Ions are arranged in a regular repeating pattern in which positive charges cancel out negative charges. Each ion is attracted to all surrounding oppositely charged ions so the lattice as a whole carries no net charge.
When atoms form ions through ionic bonding, they achieve the electronic configuration of a .......... gas.
When atoms form ions through ionic bonding, they achieve the electronic configuration of a noble gas.
Why are 2 fluoride ions needed for every calcium ion in calcium fluoride (CaF₂)?
Calcium forms a Ca²⁺ ion by losing 2 electrons. Each fluorine atom can only accept 1 electron, forming an F^- ion. Two F^- ions are needed to cancel the 2+ charge of the Ca²⁺ ion, making the overall compound neutral.
What are the conventions for drawing an ionic dot-and-cross diagram?
Only outer-shell electrons are shown, represented as dots and crosses. Brackets are drawn around each ion to show that the charge is spread evenly, and the ionic charge is written at the top right-hand corner of each bracket.
Define atomic radius
Atomic radius is the distance between the nucleus and the outermost electron of an atom. It is measured by halving the distance between the nuclei of two bonded atoms of the same element.
Why does atomic radius decrease across a period?
Across a period, nuclear charge increases as more protons are added, but the number of electron shells stays the same so shielding is constant. The greater nuclear charge pulls the outer electrons closer to the nucleus, reducing the atomic radius.
True or False?
Shielding increases across a period in the periodic table.
False.
Elements across a period all have the same number of electron shells, so the shielding effect remains constant. It is the increasing nuclear charge that causes atomic radius to decrease.
Define ionic radius
Ionic radius is a measure of the size of an ion. It increases with greater negative charge (more electrons gained) and decreases with greater positive charge (electrons lost, same nuclear charge).
Why is a negative ion larger than its parent atom?
Gaining electrons increases the number of electrons around the same nucleus. The nuclear charge is unchanged, so the electrostatic pull on each electron is weaker, allowing the electron cloud to expand and increasing the ionic radius.
What factors determine the strength of an ionic bond?
Ionic bond strength depends on the charge and size of the ions. Higher ionic charges and smaller ionic radii produce a greater charge density and therefore stronger ionic bonds.
Ions with the same electronic configuration but different numbers of protons are called .......... ions.
Ions with the same electronic configuration but different numbers of protons are called isoelectronic ions.
How does ionic radius change across a series of isoelectronic ions such as N^3-, O^2-, F^-, Na⁺, Mg²⁺, Al³⁺?
The ionic radius decreases across this series. All ions have the same electronic configuration, but the number of protons increases. The greater nuclear charge pulls the electrons more strongly inward, reducing the ionic radius.
True or False?
The ionic radius of a positive ion increases as the positive charge increases.
False.
Ionic radius decreases with increasing positive charge. Losing more electrons leaves fewer electrons subject to the same nuclear charge, so the electrostatic attraction per electron is stronger and the ion is smaller.
Define polarisation (of an anion)
Polarisation is the distortion of the electron density of an anion caused by the electric field of a nearby cation, introducing covalent character into an otherwise ionic bond.
Define polarising power
Polarising power is the ability of a cation to distort (polarise) a nearby anion. It is greater for cations with a high charge density, meaning those that are small and highly charged.
What factors give a cation high polarising power?
A cation has high polarising power when it is small and highly charged. Both features increase the charge density of the cation, allowing it to exert a stronger pull on the electron cloud of a nearby anion.
What makes an anion highly polarisable?
An anion is more easily polarised when it has a large ionic radius. Outer electrons are further from the nucleus and held less tightly, so they are more easily distorted by the electric field of a nearby cation.
True or False?
A larger cation has greater polarising power than a smaller cation of the same charge.
False.
A larger cation has lower polarising power. Its lower charge density means it exerts a weaker pull on the electron cloud of a nearby anion. For example, K⁺ has lower polarising power than Li⁺.
When an anion is polarised by a cation, .......... character is introduced into the bond.
When an anion is polarised by a cation, covalent character is introduced into the bond.
Why can the theoretical lattice energy of an ionic compound differ from the experimentally measured value?
The theoretical model assumes perfect spherical ions with purely electrostatic interactions. In reality, polarisation of the anion by the cation introduces covalent character, causing the measured lattice energy to differ from the theoretical prediction.
Why does Mg²⁺ have a greater polarising power than Na⁺?
Mg²⁺ has a greater charge than Na⁺ and a similar (or smaller) ionic radius, giving it a higher charge density. The stronger electric field of Mg²⁺ distorts a nearby anion more effectively.
Define metallic bond
A metallic bond is the strong electrostatic force of attraction between positively charged metal ions and the surrounding sea of delocalised electrons in a giant metallic lattice.
What are delocalised electrons in a metal?
Delocalised electrons are outer-shell electrons that are not bound to any individual metal atom. They move freely throughout the metallic lattice, forming a 'sea' of electrons that holds the positive metal ions together.
Why do metals conduct electricity?
Metals conduct electricity because delocalised electrons are free to move and carry charge through the lattice. When a potential difference is applied, electrons enter one end and displace others at the far end, allowing current to flow.
Why are metals malleable and ductile?
Layers of positive metal ions can slide over one another into new positions. The delocalised electrons move with the layers, maintaining the electrostatic forces without breaking the metallic bonds.
True or False?
Metals have low melting points because metallic bonds are weak.
False.
Metallic bonds are strong electrostatic forces between delocalised electrons and positive metal ions. They require large amounts of energy to overcome, so metals generally have high melting points.
When other atoms, such as carbon atoms, are added to a pure metal structure, the resulting mixture is called an .......... .
When other atoms, such as carbon atoms, are added to a pure metal structure, the resulting mixture is called an alloy.
What three factors increase the strength of a metallic bond?
1. Increasing the number of delocalised electrons per metal atom
2. Increasing the positive charge on the metal ions
3. Decreasing the size of the metal ions
Why are alloys stronger than pure metals?
In an alloy, atoms of different sizes are present. These disrupt the regular layers of metal ions, preventing the layers from sliding over each other easily and making the structure harder and stronger.
True or False?
Metals conduct heat only through the vibration of positive ions in the lattice.
False.
Heat conduction in metals involves both vibration of positive ions and the movement of delocalised electrons. Electrons convert kinetic energy to heat when they collide with metal atoms, transferring energy through the structure.

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