C3. Structure and Bonding Flashcards
What type of bonding occurs between non-metal atoms?
Covalent bonding
What type of bonding occurs between metal atoms?
Metallic bonding
What type of bonding occurs between non-metal and metal atoms
Ionic Bonding
State the three types of bonding
Covalent, Metallic and Ionic
Why do atoms bond?
Atoms bond to achieve a greater level of stability, which is reached when the atom obtains a full outer shell of electrons
What does a dot and cross diagram?
Shows the transfer of electrons between atoms to form ions in an ionic bond
In the formation of an ionic compound, which atoms gain electrons?
Non metals atoms gain electrons
What is formed when an atom loses electrons?
When an atom loses electrons, it formed a positively charged ion
What happens to a Group 7 atom when it reacts with a Group 1 atom?
When a Group 7 atoms react with a Group 1 atom, the Group 7 atom: gains an electron. Becomes negatively charged/ becomes a 1- ion
What type of forces hold ionic compounds together?
Ionic compounds are held together by strong electrostatic forces of attraction between oppositely charged ions
What is the structure of ionic compounds called?
Giant Ionic Lattice
Are ionic compounds usually solid or liquid at room temperature?
Ionic compounds are usually solid at room temperature
What are electrostatic forces?
Electrostatic forces are the attractive force between charged particles
In an ionic lattice, what direction do the electrostatic forces act in?
Electrostatic forces act in all directions
In an ionic solution, what moves to all electrical current to flow.
The movement of ions allow electrical current to flow
Describe the structure of a giant ionic lattic
A series of positively charged and negatively charged ions arranged in an alternating pattern
What does the 3D ball and stick model show about ionic bonds that is inaccurate?
It inaccurately represents ionic bonds as sticks between ions whereas in reality an ionic bond is an electrostatic force of attraction that acts in all directions around am ion
What is represented by a short straight line between two atoms?
A short straight line between two atoms represents a covalent bond
What is a covalent bond?
A type of chemical bond where atoms shares pairs of electrons with each other
What type of materials form a covalent bond?
Non-metals
What makes each atom more stable in a covalent bond?
Sharing electrons in the covalent bond allows each atom to achieve an electron configuration similar to a noble gas
What is formed when a group of two or more covalently bond together?
A compound is formed when a group of two or more atoms covalently bond together
What is the smallest molecule?
H₂
What is the difference between simple covalent molecules and giant covalent structures?
Simple covalent molecules are small and can be separated into individual molecular units without breaking chemical bonds, while giant covalent structures form huge continuous networks of atoms that cannot be separated without breaking bonds
What is metallic bonding?
Metallic bonding is the strong electrostatic force of attraction between delocalised electrons and positively charged metal ions
What are delocalised electrons in metals?
Electrons in metals that do not belong to any particular metal atom and are free to move throughout the metal lattice
Describe the structure of a metal
Positive metal ions arranged in a regular pattern with a “sea” of delocalised electrons moving freely between them
What are delocalised electrons?
Electrons that are no longer belong to any specific metal atom
What type of structure do metals have?
Giant lattice structure
What is melting?
When a solid changes into a liquid
What is boiling?
When a liquid changes into a gas at a specific temperature
What is freezing?
When a liquid changes into a solid
What is evaporation?
When a liquid changes into a gas.
What is condensation?
When a gas changes into a liquid, usually on cooling
State three limitations of particle theory
Does not account for forces of attraction between the particles
Considers for all particles as spherical in shape
Does not consider the size of the particles
What happens to particles when a substance boils?
When a substance boils particles gain enough energy for the intermolecular forces to break and the molecules to escape from the surface of liquid
Why can ionic compound conduct electricity when molten or in a solution
The ions are free to move and carry a charge
Describe the structure of a giant ionic lattice.
A series of positively charged and negatively charged ions arranged in an alternating pattern
Why do ionic compounds have a high melting and boiling point?
They have a giant structure
Lots of energy is needed to overcome the strong electrostatic attraction between oppositely charged ions
In an ionic lattice, what direction do the electrostatic forces act in?
All directions
Why can solid ionic compounds not conduct electricity?
Solid ionic compounds cannot conduct electricity because the ions cannot move and carry a charge
What is the difference between covalent bonds and intermolecular forces?
Strong bonds that holds atoms together within a molecule while intermolecular forces are weak attractive forces that exist between different molecules
What are simple molecular structures?
Small molecules with covalent bonds, which have weak forces between the molecules
Why are covalent compounds generally poor conductors of electricity?
Covalent compounds are generally poor conductors of electricity because they do not contain free ions or electrons to carry the current
What happens to melting and boiling points as the relative molecular mass of a substance increases?
As the relative molecular mass of a substance increases, the melting and boiling points also increase due to the increased number of electrons and stronger intermolecular forces
Why do simple molecular structures have low melting and boiling points?
Simple molecular structures have low melting and boiling points due to weak intermolecular forces which requires small amounts of energy to overcome
What is a polymer
A substance consisting of very large molecules made by linking together large numbers or smaller molecules called monomers
What is a monomer?
A small molecule that can be bonded to other identical molecules to form a polymer
What exists between polymer chains?
Intermolecular forces
What are giant covalent structures?
Solids with high melting points consisting of a huge number of non-metal atoms bonded to other non-metal atoms via strong covalent bonds
Name three examples of giant covalent structures
Diamond, graphite and silicon dioxide
Why do giant covalent structures have high melting points?
There are many strong covalent bonds between atoms which require lots of energy to overcome
What is an alloy?
A mixture of metals where the metals are mixed together physically but are not chemically combined
State an advantage of using alloys over pure metals
Greater strength
Greater hardness
Increased resistance to corrosion
Increased resistance to extreme temperatures
Describe the structure of an alloy
Alloy contains atoms of different sizes which distort the regular arrangement of atoms
Explain why alloys are harder than pure metals
The increased hardness and strength of an alloy is caused by the different size of atoms which distort the regular arrangements of atoms preventing the layers of atoms from sliding over each other easily
How do properties of alloys differ from pure metals
Alloys often have greater strength/hardness, or resistance to corrosion/ extreme temperatures compared to pure metals
Why do metals generally have high melting points?
They have giant structures
There are strong electrostatic forces of attraction between the positive metal ions and the negative delocalised electrons
These forces need lots of energy to break
Why are metals malleable?
Metals are malleable because the atoms are arranged in layers which can slide over each when force is applied
What is a metallic bond?
The strong force of attraction between the positive metal ions and the delocalised electrons in a metal structure
How do metals conduct heat?
The delocalised electrons are free to move and transfer thermal energy through the structure
How do metals conduct electricity?
The delocalised electrons are able to move through the structure and carry a charge
Why does diamond not conduct electricity?
Diamond does not conduct electricity because all of the outer shell electrons are held in the covalent bonds and there are no freely moving delocalised electrons to carry the current
State the properties of diamond
High melting and boiling point
Does not conduct electricity
Is extremely hard
Why is diamond hard?
Each carbon atom is bonded to four other carbon atoms via strong covalent bonds
Describe the structure of graphite
Each carbon atom is bonded to three others
There are hexagonal layers
There is one free/ delocalised electrons per carbon atom
What are the properties of graphite?
It conducts electricity and heat
It has a high melting point and booking point
It is soft and slippery
Explain why graphite conducts electricity
Graphite conducts electricity because it has delocalised electrons that can move and carry a charge throughout the structure
Why is graphite soft and slippery?
Graphite is soft because there are weak intermolecular forces between the layers, which allows the layers to slide over each other
List four properties of graphene
Extremely strong but light
Conducts heat and electricity
Transparent
Flexible
Why is graphene an excellent conductor of electricty?
It has delocalised electrons which can move and carry a charge
What are fullerenes?
Molecules of carbons atoms with hollow shapes
What are carbon nanotubes?
A type of fullerene produced by rolling graphene into a cylinder
State two properties of carbon nanotubes
High tensile strength
Ability to conduct electricity
What is a potential use of fullerenes in medicine?
Fullerenes are hollow so they can be used to trap drug molecules and deliver them where needed
Why can carbon nanotubes conduct electricity?
There are delocalised electrons which are free to move and carry a charge
What applications is graphene useful im?
Electronics and composites
