Year 11 ATAR Chemistry Bonding

Why do atoms bond?

Atoms bond to achieve stable electron configurations by either exchanging or sharing electrons.

What are the four main types of chemical bonds?

Metallic, Ionic, Covalent Molecular, and Covalent Network.

What is the basic atomic structure formed in metallic bonding?

Metal cations that are tightly packed together with delocalised valence electrons moving freely between them.

How do metallic elements achieve stability?

By losing their valence electrons to become cations, achieving a noble gas electron configuration.

What is the role of delocalised electrons in metallic bonding?

They create electrostatic attraction between positive cations and help bond the cations in the metallic structure.

What do Lewis structures represent?

They show the bonding present in a structure using valence electrons, with elements represented by their symbols.

What are the common physical properties of metals due to metallic bonding?

Metals are relatively dense, hard, have high melting and boiling points, are malleable and ductile, and are good conductors of electricity and heat.

Why are metals considered dense?

Because the spherical cations are tightly packed together in the metallic structure.

What explains the hardness of metals?

The compact arrangement of metal cations and the strength of the bonds within the structure.

What causes metals to have high melting and boiling points?

The strong electrostatic attraction between delocalised electrons and metal cations requires a large amount of heat energy to break.

What does it mean for metals to be malleable and ductile?

Malleable means they can be bent into flat sheets, while ductile means they can be stretched into thin wires.

How do metallic bonds behave when cations are forced to move past each other?

The bonds can change direction without breaking due to the non-directional nature of delocalised electrons.

What increases the strength of metal alloys?

The combination of different metals can enhance the overall strength of the alloy.

What is required for a substance to conduct electricity?

It must have freely moving charged particles; in metals, this is provided by delocalised valence electrons.

How do metals conduct heat?

Heat is conducted through metals via highly kinetic delocalised electrons.

What is the structure of ionic compounds?

Ionic compounds consist of cations and anions bonded in an alternating lattice pattern.

What holds together the ions in ionic bonding?

Strong electrostatic attractive forces between oppositely charged ions.

What is the significance of electron sharing in covalent bonding?

It allows atoms to achieve stable electron configurations by sharing electrons.

What distinguishes covalent molecular bonding from covalent network bonding?

Covalent molecular bonding involves discrete molecules, while covalent network bonding involves a continuous network of atoms.

How does the electron configuration of sodium change when it forms a cation?

Sodium loses one valence electron, changing from Na (2, 8, 1) to Na+ (2, 8).

What is the nature of metallic bonds?

They are fluid-like and can change direction without breaking the metallic lattice structure.

What is the role of mobile charged particles in electrical conductivity?

Mobile charged particles, such as delocalised electrons in metals, allow for the conduction of electrical current.

What is the relationship between heat conduction and metallic bonding?

The kinetic energy of delocalised electrons facilitates the conduction of heat through metals.

What happens to metallic elements to achieve stability?

They lose their valence electrons, becoming like a noble gas in configuration.

What is formed when a metallic element donates its valence electrons to a non-metal?

A cation (positive ion) and an anion (negative ion) are formed.

What are the common physical properties of ionic substances?

Ionic substances are usually hard, brittle, have high melting and boiling points, poor electrical conductors in solid state, and good electrical conductors in liquid state or when dissolved in water.

Why do ionic compounds have high melting and boiling points?

They are held together by strong electrostatic forces between oppositely charged ions, requiring a lot of energy to overcome.

Under what conditions can ionic compounds conduct electricity?

Ionic compounds can conduct electricity when melted to form a liquid or dissolved in water to form an aqueous solution.

Why can't ionic compounds conduct electricity in solid state?

In solid state, the ions are held in fixed positions and cannot move.

Why are ionic crystals hard?

They are hard due to tight packing of ions in a lattice structure, which resists mechanical pressure.

What makes ionic crystals brittle?

When mechanical pressure is applied, ions of similar charges may be forced closer together, causing electrostatic repulsion that can split or disorient the lattice.

What is a Lewis structure?

A simplified way of showing the bonding present in a structure, representing only the valence electrons.

How are valence electrons represented in Lewis structures?

Valence electrons are placed into four box areas around the element symbol, paired only if there are no empty boxes.

How are ions represented in Lewis structures?

Ions are represented by showing the original valence shell electrons, using square brackets and a charge.

How do you represent ionic compounds in Lewis structures?

Draw the two ion structures next to each other and include coefficients to show ratios.

What is the relationship between the size of a molecule and temperature change during evaporation?

The larger the molecule, the lower the temperature dropped to.

What happens to heat energy when molecules evaporate from a liquid?

They take some of the heat energy with them.

What must happen for a molecule to evaporate?

It must first break the intermolecular bonds.

How do stronger intermolecular bonds affect evaporation?

Stronger intermolecular bonds make it more difficult for molecules to evaporate, resulting in a smaller temperature change.

What is the significance of intermolecular bonds in larger molecules?

Larger molecules tend to have stronger intermolecular bonds.

What is the role of valence electrons in ionic bonding?

Valence electrons are transferred from metals to non-metals, forming cations and anions that bond ionically.

What is an example of a metallic element losing electrons?

Sodium (Na) loses one electron to become Na+.

What is an example of a non-metal gaining electrons?

Chlorine (Cl) gains one electron to become Cl-.

What are the two types of ions formed in ionic bonding?

Cations (positively charged) and anions (negatively charged).

What is the effect of mechanical pressure on ionic crystals?

It can cause ions of similar charges to repel each other, leading to the breaking or disorientation of the crystal lattice.

What is the significance of the ionic lattice structure?

It contains a large number of ions held together by ionic bonds, contributing to the physical properties of ionic compounds.

What are covalent molecular substances formed by?

Non-metal atoms covalently bonding together to achieve stable electron configurations.

What type of forces attract individual molecules in covalent molecular substances?

Weak intermolecular forces, also known as Van der Waals forces.

What do Lewis Structures represent?

A simplified way of showing the bonding present in a structure, focusing on valence electrons.

How are valence electrons represented in Lewis Structures?

They are placed into four box areas around the element symbol, paired only when no empty boxes are available.

What is the goal when creating covalent molecular Lewis Structures?

To arrange individual atoms so that all achieve a stable outer shell.

List some examples of covalent molecules that contain single bonds.

H2, OF2, H2S, CH4, NH3, C2H6, CH3OH.

What types of covalent bonds can be present in molecules?

Single, double, triple, and coordinate covalent bonds.

What is a coordinate covalent bond?

A bond where a lone pair of electrons from one atom fills a missing space in another atom.

What is the mathematical approach to determine the number of bonds in a molecule?

Calculate the number of valence electrons, determine the required valence electrons, find the difference, and divide by two.

What are the typical physical properties of covalent molecular substances?

Low melting and boiling points, soft/waxy solids, can be gas or liquid at room temperature, can have odors, and are usually non-conductors.

Why do covalent molecular substances have low melting and boiling points?

Due to relatively weak intermolecular forces between molecules.

What are some examples of covalent network substances?

Carbon (diamond, graphite, fullerenes), silicon dioxide, and silicon carbide.

What is unique about graphite among covalent network substances?

It can conduct electricity due to delocalized electrons in its two-dimensional layers.

What are fullerenes?

Structures made from carbon atoms joined together to form balls, cages, or tubes, known for their strength and electrical properties.

What makes covalent network substances very hard and inert?

The strength of the covalent bonds and the three-dimensional lattice structure.

What is the general property of covalent network substances regarding conductivity?

They are generally non-conductors, except for graphite.

What is the melting point and boiling point of covalent network substances?

They have high melting and boiling points.

What is the significance of delocalized electrons in graphite?

They allow for electrical conductivity and enable the layers to slip past each other, making graphite useful as a lubricant.

What are some compounds that exhibit both ionic and covalent bonding?

ClO3-, PO43-, SO32-, NaClO, CaCO3, Ba(OH)2, NaHCO3, Na2SO4.

What is the role of carbon in covalent molecular structures?

Carbon can form 'backbones' within molecules, allowing for complex structures.

What is a dichotomous key used for in bonding structures?

To identify the four types of bonding structures: metallic, ionic, covalent molecular, and covalent network.

What are the characteristics of covalent network bonding?

Very hard, high melting and boiling points, and generally non-conductive except for graphite.

What is the importance of intermolecular forces in covalent molecular substances?

They determine the physical properties such as melting point, boiling point, and state at room temperature.