Structure and bonding Flashcards
What is a compound?
A substance in which atoms of two or more elements are chemically combined.
What type of bonding occurs between a metal and a non-metal?
Ionic bonding.
What type of bonding occurs between non-metals?
Covalent bonding.
What type of bonding occurs between metals?
Metallic bonding.
Define ionic bonds.
Strong electrostatic forces of attraction between oppositely charged ions.
How do atoms achieve stability in ionic bonding?
By having a full outer electron shell through the transfer of electrons.
What happens to metal atoms in an ionic bond?
They lose electrons and become positive ions, called cations.
What happens to non-metal atoms in an ionic bond?
They gain electrons and form negative ions.
What causes ions in ionic bonds to stick together?
Electrostatic forces due to opposite charges.
What is the electronic structure of ions produced by metals in groups 1 and 2 and non-metals in groups 6 and 7?
The electronic structure of a noble gas (Group 0 - full outer shell).
What diagram can represent the electron transfer during the formation of an ionic compound?
A dot and cross diagram.
Fill in the blank: In an ionic bond, elements all have a _______.
full outer shell.
Provide an example of an ionic compound.
Sodium chloride, NaCl.
What is the charge of sodium ions after bonding?
Positive (+).
What is the charge of chloride ions after bonding?
Negative (-).
True or False: Ionic bonds involve the sharing of electrons.
False.
What should be included in a cross and dot drawing?
Arrow and the word transfer showing the movement of electrons
Include before and after transfer with an arrow separating the two sides, and show all shells unless instructed otherwise.
In a cross and dot drawing, where should the electric configuration be placed?
Underneath the element in square brackets
The electric configuration represents the distribution of electrons in the atom.
How should charges be displayed in a cross and dot drawing?
Outside the square brackets around the atoms on the second half, after the element and after the electrical configuration
This indicates the ionic charge of the elements involved.
What is the first step in writing an ionic formula?
Find the charge of the ion
This is crucial for determining how the ions will combine.
Why must charges balance out in an ionic formula?
Because ionic compounds are neutral
The total positive charge must equal the total negative charge to maintain neutrality.
What is the charge of an ion in Group 1?
+1
What is the charge of an ion in Group 2?
+2
What is the charge of an ion in Group 3?
+3
What is the charge of an ion in Group 5?
-3
What is the charge of an ion in Group 6?
-2
What is the charge of an ion in Group 7?
-1
Why do Group 1 metals become +1 charged?
They lose one outer electron to achieve a full outer shell
Why do Group 2 metals become +2 charged?
They lose two outer electrons to achieve a full outer shell
Why do Group 3 metals become +3 charged?
They lose three outer electrons to achieve a full outer shell
Why do Group 5 non-metals become -3 charged?
They gain three outer electrons to achieve a full outer shell
Why do Group 6 non-metals become -2 charged?
They gain two outer electrons to achieve a full outer shell
Why do Group 7 non-metals become -1 charged?
They gain one outer electron to achieve a full outer shell
What is covalent bonding?
Strong electrostatic attraction between positively charged nuclei and shared pair of electrons
How do atoms achieve stability in covalent bonding?
By sharing electrons between two non-metal atoms to form molecules
True or False: Group 1 elements gain electrons to achieve a full outer shell.
False
Fill in the blank: The charge of a Group 6 ion is ______.
-2
What is metallic bonding?
Strong electrostatic attraction between the sea of delocalised electrons and the metal cations
How are atoms arranged in a metal?
Packed tightly and regularly in layers in a giant lattice
What are delocalised electrons?
Electrons in the outer shell of the metal atoms that become separated and are free to move through the structure
What forms the lattice in metallic bonding?
A lattice of cations surrounded by a sea of delocalised electrons
What is the primary force that holds metal ions together?
Electrostatic attraction to the delocalised electrons
What are the properties of pure metals?
High melting and boiling point, high density, good conductors of electricity and heat, malleable and ductile
Why do pure metals have high melting and boiling points?
Strong electrostatic attractions require a lot of energy to break down intermolecular forces
What contributes to the high density of metals?
Atoms are packed together tightly due to strong electrostatic attractions
Why are metals good conductors of electricity?
Delocalised electrons move through the structure carrying electrical charge
How do metals conduct heat?
Delocalised electrons take in heat energy, move faster, and spread throughout the structure
What does malleable mean?
Can be hammered into shape
What does ductile mean?
Can be drawn into a wire
What are alloys?
Made of two or more elements, one of which is a metal
How do alloys differ from pure metals in terms of structure?
Different sizes of atoms distort the lattice making it harder for layers to slide
What effect does the distortion of the lattice in alloys have?
Makes alloys harder than pure metals
What is ionic bonding?
The strong force of electrostatic attraction between oppositely charged ions.
What are ionic compounds?
A giant structure of ions held together by ionic bonds.
What is the structure of ionic compounds?
Giant ionic lattices.
What are the melting and boiling points of giant ionic structures?
High melting and boiling points.
Why do ionic compounds have high melting and boiling points?
Strong forces of electrostatic attraction between oppositely charged ions require lots of energy to break.
When can ionic compounds conduct electricity?
When molten or in solution.
Why can ionic compounds conduct electricity when molten or in solution?
The ions are free to move and carry the charge.
Can ionic compounds conduct electricity as solids?
No, because the ions can’t move.
What are simple covalent molecules?
Molecules between two nonmetals held together by covalent bonds.
What is a covalent bond?
The strong force of electrostatic attraction between the nuclei and the shared pair of electrons.
Give examples of simple covalent molecules.
H2, N2, O2, CH4, H2O.
What type of forces exist in simple covalent structures?
Intermolecular forces.
What are the melting and boiling points of simple covalent structures?
Low melting and boiling points.
Why do simple covalent structures have low melting and boiling points?
Weak intermolecular forces require little energy to overcome.
How does the melting point change with the size of the molecule in simple covalent structures?
It gets higher as the molecule gets bigger.
Why do larger simple covalent molecules have higher melting points?
They have more electrons, leading to stronger intermolecular forces.
Do simple covalent structures conduct electricity?
No, because there are no delocalised electrons or ions.
What are giant covalent structures?
Structures linked by strong covalent bonds, requiring lots of energy to break.
What are some main examples of giant covalent structures?
Diamond, graphite, and silicon dioxide.
What is unique about the structure of diamond?
Made up of carbon atoms only, each forming four strong covalent bonds.
What type of structure does diamond have?
Tetrahedral structure.
What is the melting and boiling point of diamond?
High melting and boiling point due to strong covalent bonds
Each carbon forms strong covalent bonds with other carbon atoms, requiring much energy to break these bonds.
Why is diamond considered rigid and hard?
Forms strong covalent bonds in a giant tetrahedral structure
The tetrahedral arrangement contributes to its rigidity.
Does diamond conduct electricity? Why or why not?
Doesn’t conduct electricity because there are no free moving ions or electrons
Each carbon atom uses all four electrons to bond with four others.
What type of bonding occurs between carbon atoms in graphite?
Each carbon atom forms 3 strong covalent bonds
Graphite consists of layers of hexagonal rings with no covalent bonds between layers.
What is unique about the electrons in graphite?
One delocalised electron per carbon atom
This delocalisation allows conductivity.
What are the properties of graphite?
High melting and boiling point, soft and slippery, can conduct electricity
The properties arise from strong covalent bonds and the presence of delocalised electrons.
What is the chemical composition of silicon dioxide?
Made of SiO2 (two oxygens for each silicon)
The structure contributes to its high melting point.
What gives silicon dioxide its hardness?
Strong covalent bonds in a tetrahedral structure
Requires lots of energy to break down these bonds.
What is graphene?
A single layer of graphite with useful electronic properties
Contains one delocalised electron.
What are fullerenes?
Molecules of carbon atoms with hollow shapes based on hexagonal rings
Some spherical shapes are used for drug delivery.
What are carbon nanotubes?
Cylindrical fullerenes with very high length to diameter ratio
Used in nanotechnology, electronics, and composites.
Fill in the blank: Diamond has a _______ structure that contributes to its hardness.
tetrahedral
True or False: Graphite can conduct electricity.
True
Due to the presence of delocalised electrons.
Fill in the blank: Silicon dioxide has a high melting point because of many strong _______ bonds.
covalent
What is metallic bonding?
A strong force of electrostatic attraction between positive metal ions and a sea of delocalised electrons.
Metals exist in a giant structure.
What are the properties of metallic lattices?
- Conduct electricity
- High melting points
- Malleable
Delocalised electrons can move through the structure, strong metallic bonds require lots of energy to break, and regular layers of positive metal ions can slide over each other easily.
What type of bonding is found in giant ionic structures?
Ionic bonding
Characterized by high melting points due to many strong ionic bonds.
Do giant ionic structures conduct electricity?
Only when molten or in solution.
Ions can move and carry charge.
What type of bonding is found in giant metallic structures?
Metallic bonding
Characterized by high melting points due to many strong metallic bonds.
Do giant metallic structures conduct electricity?
Yes.
Delocalised electrons can carry charge through the structure.
What type of bonding is found in simple covalent structures?
Covalent bonding
Characterized by low melting points due to weak intermolecular forces.
Do simple covalent structures conduct electricity?
No.
They do not have free-moving charged particles.
What type of bonding is found in giant covalent structures?
Covalent bonding
Characterized by high melting points due to many strong covalent bonds.
What is soda-lime glass made from?
Heating sand, sodium carbonate, and limestone (calcium carbonate).
Used in day-to-day applications.
What is borosilicate glass made from?
Heating sand and boron trioxide.
Has a higher melting point and is used in laboratories.
What are ceramics?
Materials such as brick, china, and porcelain.
Made by shaping wet clay and heating it to a high temperature in a furnace.
What happens to the surface area to volume ratio when one side of a particle is decreased by a factor of 10?
It increases 10 times.
This is a principle in nanotechnology.
What is the significance of the SA:V ratio in nanoparticles?
Nanoparticles have different properties from bulk materials due to the different SA:V ratio
What are some applications of nanoparticles?
Nanoparticles can be used for:
* Catalysts
* Sun cream
* Deodorants
* Medicine
* Electronics
True or False: Smaller quantities of nanoparticles might be as effective as larger bulk of the material.
True
What is a concern regarding the use of nanoparticles?
More research is needed as they could be harmful to health and the environment
Fill in the blank: Nanoparticles have different properties from the bulk materials because of the different _______.
SA:V ratio
