C2 Ai Flashcards
What are ions?
Ions are formed when atoms gain or lose electrons.
What do ions always have after their formula?
Ions will always have a ‘+’ or ‘-‘ sign after the formula.
What does a ‘+’ sign indicate about an ion?
A ‘+’ sign tells you the ion is positive.
What does a ‘-‘ sign indicate about an ion?
A ‘-‘ sign tells you the ion is negative.
Why do atoms form ions?
Atoms form ions to achieve a full outer shell, similar to a noble gas.
What charge does an ion have if 2 electrons are lost?
The charge is 2+.
What charge does an ion have if 3 electrons are gained?
The charge is 3-.
Which groups of the periodic table typically form positive ions?
Group 1 and 2 elements are metals that lose electrons to form positive ions.
Which groups of the periodic table typically form negative ions?
Group 6 and 7 elements are non-metals that gain electrons to form negative ions.
What is the charge of ions formed by Group 1 elements?
Group 1 elements form 1+ ions.
What is the charge of ions formed by Group 2 elements?
Group 2 elements form 2+ ions.
What is the charge of ions formed by Group 6 elements?
Group 6 elements form 2- ions.
What is the charge of ions formed by Group 7 elements?
Group 7 elements form 1- ions.
Fill in the blank: A sodium atom (Na) loses 1 electron to form a _______.
sodium ion (Na+).
Fill in the blank: A magnesium atom (Mg) loses 2 electrons to form a _______.
magnesium ion (Mg2+).
Fill in the blank: A chlorine atom (Cl) gains 1 electron to form a _______.
chloride ion (Cl-).
Fill in the blank: An oxygen atom (O) gains 2 electrons to form an _______.
oxide ion (O2-).
True or False: You need to memorize the ions formed by all elements.
False.
What can you use to predict the ions formed by elements in Groups 1, 2, 6, and 7?
You can look at the periodic table.
What is ionic bonding?
Transfer of electrons between metals and non-metals
Metals lose electrons to form positively charged ions, while non-metals gain electrons to form negatively charged ions.
What happens to metal atoms during ionic bonding?
Metal atoms lose electrons to form positively charged ions.
What do non-metal atoms do during ionic bonding?
Non-metal atoms gain electrons to form negatively charged ions.
What do dot and cross diagrams represent?
Arrangement of electrons in an atom or ion.
In dot and cross diagrams, how is each electron represented?
Each electron is represented by a dot or a cross.
What is the ionic bond in sodium chloride (NaCl)?
Sodium atom loses an electron to form Na+, chlorine atom gains an electron to form Cl-.
What occurs in magnesium oxide (MgO) during ionic bonding?
Magnesium loses two electrons to form Mg2+, oxygen gains electrons to form O-.
What do the dots and crosses in dot and cross diagrams represent?
Dots represent electrons from one atom, crosses represent electrons from another atom.
What ions are formed when magnesium loses two electrons?
Mg2+ ion.
What type of ions do chlorine atoms form in magnesium chloride (MgCl2)?
Two Cl- (chloride) ions.
What are the limitations of dot and cross diagrams?
They do not show the structure, size of ions, or how they are arranged.
True or False: Dot and cross diagrams show different types of electrons.
False.
Fill in the blank: The forces that hold the ions together in an ionic compound are called _______.
[ionic forces].
What type of questions can help practice drawing dot and cross diagrams?
Questions about how different elements form ionic compounds.
What are ionic bonds?
Forces that hold ions together in an ionic compound
Ionic bonds form between positively and negatively charged ions.
What are the characteristics of ionic compounds?
Ionic compounds have high melting points and high boiling points
This is due to the strong ionic bonds that require a lot of energy to break.
Why can’t solid ionic compounds conduct electricity?
The ions are held in place and cannot move
Solid ionic compounds are rigid and do not allow free movement of ions.
How do ionic compounds conduct electricity when dissolved in water?
The ions are free to move in the solution
When dissolved, ionic compounds dissociate into their respective ions.
What is the empirical formula of an ionic compound based on?
The balance of the charges of the ions
The overall charge on the compound must equal zero.
What is an example of how to determine the empirical formula of a compound?
Count the number of ions and balance their charges
For example, K+ and O2- ions in potassium oxide.
What does a dot and cross diagram represent?
The arrangement of electrons in an ionic compound
It visually shows how electrons are transferred between atoms.
What does a 3D model of an ionic compound show?
The arrangement of ions in space and their relative sizes
It helps visualize the structure but may not accurately represent ion sizes.
True or False: Ionic compounds have ordered arrangements of ions.
True
Ionic compounds exhibit a regular pattern in their crystal lattice structure.
Fill in the blank: The empirical formula shows the _______ of particles in an ionic compound.
smallest ratio
The empirical formula represents the simplest whole number ratio of ions.
What happens to ionic compounds when they are molten?
They can conduct electricity
In molten form, the ions are free to move, allowing for electrical conductivity.
What is the charge of a potassium ion?
1+
Potassium is in Group 1 of the periodic table and forms a 1+ charge.
What charge does an oxide ion have?
2-
Oxygen is in Group 6 and typically forms a 2- charge.
What are covalent bonds?
Covalent bonds are electrostatic forces and are very strong.
What do atoms share in covalent bonding?
Atoms share electrons in their outer shells.
How many extra shared electrons does an atom gain from forming a covalent bond?
One extra shared electron for each covalent bond formed.
What do dot and cross diagrams represent?
Dot and cross diagrams show which atoms the electrons in a covalent bond come from.
What information do dot and cross diagrams not provide?
They don’t show how the atoms are arranged or how big the atoms are compared to each other.
In displayed formulas, how is a single covalent bond represented?
A single line between atoms.
How is a double covalent bond represented in displayed formulas?
Two lines between atoms.
What do displayed formulas effectively show?
They show how atoms are connected in large molecules.
What is a limitation of displayed formulas?
They don’t show the 3D structure of the molecule.
What do 3D models show?
They show the atoms, the covalent bonds, and how they’re arranged.
What can be confusing about 3D models?
They can be confusing for large molecules.
What is a molecular formula?
A molecular formula shows how many atoms of each element are in a molecule.
How do you find the molecular formula of a compound from a diagram?
By counting up how many atoms of each element there are.
Fill in the blank: A molecule of ethane has ______ carbon atoms and ______ hydrogen atoms.
2 carbon atoms and 6 hydrogen atoms.
What is the molecular formula of ethane?
C2H6.
What bonding diagram should be drawn for a molecule of ammonia?
A dot and cross diagram.
What are simple molecular substances made up of?
Molecules that contain a few atoms joined together by covalent bonds.
Name three common examples of simple molecular substances.
- Chlorine, Cl
- Hydrogen, H
- Water, H2O
What type of bond do the oxygen atoms share?
A double covalent bond.
What type of bond do the nitrogen atoms share?
A triple covalent bond.
What are the properties of simple molecular substances?
- Strong covalent bonds within molecules
- Weak intermolecular forces between molecules
- Low melting and boiling points
What is required to melt or boil a simple molecular compound?
Breaking the weak intermolecular forces.
At room temperature, most molecular substances are typically in which states?
Gases or liquids.
What happens to the intermolecular forces as molecules get bigger?
The intermolecular forces get stronger.
Why don’t molecular compounds conduct electricity?
They aren’t charged.
Fill in the blank: The melting and boiling points of simple molecular substances are very _______.
low
True or False: The covalent bonds within simple molecular substances are weak.
False
Explain why oxygen, O2, is a gas at room temperature.
Explain why nitrogen, N2, doesn’t conduct electricity.
What are simple molecular substances made up of?
Molecules that contain a few atoms joined together by covalent bonds.
Name three common examples of simple molecular substances.
- Chlorine, Cl
- Hydrogen, H
- Water, H2O
What type of bond do the oxygen atoms share?
A double covalent bond.
What type of bond do the nitrogen atoms share?
A triple covalent bond.
What are the properties of simple molecular substances?
- Strong covalent bonds within molecules
- Weak intermolecular forces between molecules
- Low melting and boiling points
What is required to melt or boil a simple molecular compound?
Breaking the weak intermolecular forces.
At room temperature, most molecular substances are typically in which states?
Gases or liquids.
What happens to the intermolecular forces as molecules get bigger?
The intermolecular forces get stronger.
Why don’t molecular compounds conduct electricity?
They aren’t charged.
Fill in the blank: The melting and boiling points of simple molecular substances are very _______.
low
True or False: The covalent bonds within simple molecular substances are weak.
False
Explain why oxygen, O2, is a gas at room temperature.
Explain why nitrogen, N2, doesn’t conduct electricity.
What is a polymer?
A polymer is a large molecule made up of many small units joined together by strong covalent bonds.
What does ‘n’ represent in the molecular formula of a polymer?
‘n’ represents a large number indicating the repeating unit is repeated many times.
What are the types of forces present in polymers?
Polymers have intermolecular forces that are generally weaker than ionic or covalent bonds.
What are giant covalent structures?
Giant covalent structures are materials where all atoms are bonded to each other by strong covalent bonds.
List three examples of giant covalent structures.
- Diamond
- Graphite
- Silicon dioxide (silica)
What are the melting and boiling points of giant covalent structures?
They have very high melting and boiling points due to the strong covalent bonds.
Do giant covalent structures conduct electricity?
No, they do not conduct electricity, except for some exceptions like graphite.
What is the repeating unit in poly(chloroethene)?
The repeating unit is made up of chloroethene.
True or False: To melt or boil a simple molecular substance, only intermolecular forces need to be broken.
True
What must be broken to melt or boil a giant covalent substance?
Very strong covalent bonds must be broken.
What type of bonds join the atoms in a polymer?
Strong covalent bonds.
Fill in the blank: The molecular formula of a polymer is represented as (C, H)a^n.
[C, H] or other units.
What type of bonds do carbon atoms form in diamond?
Each carbon atom forms four covalent bonds
This bonding arrangement contributes to diamond’s hardness.
Why is diamond considered very hard?
Due to each carbon atom forming four covalent bonds
The strength of covalent bonds requires significant energy to break.
What is the melting point characteristic of diamond?
Diamond has a very high melting point
This is because it takes a lot of energy to break the covalent bonds.
Does diamond conduct electricity?
No, diamond does not conduct electricity
This is because it has no free electrons or ions.
What is the arrangement of carbon atoms in graphite?
Carbon atoms are arranged in layers of hexagons
Each hexagon consists of six carbon atoms.
How many covalent bonds does each carbon atom form in graphite?
Each carbon atom forms three covalent bonds
This bonding arrangement contributes to the properties of graphite.
What allows the layers of graphite to move over each other?
There aren’t any covalent bonds between the layers
This property makes graphite soft and slippery.
What is the melting point of graphite like?
Graphite has a high melting point
This is due to the energy needed to break its bonds.
Can graphite conduct electricity?
Yes, graphite conducts electricity
It has free electrons that can move, similar to metals.
What is graphene?
Graphene is a sheet of carbon atoms joined in hexagons
It can be considered as one layer of graphite.
What are the properties of graphene?
Graphene is very strong and very light
It can be added to other materials to enhance strength without significant weight increase.
How does graphene conduct electricity?
Graphene contains free electrons that can move
This property makes it suitable for electronics.
What are fullerenes?
Fullerenes are molecules of carbon shaped like closed tubes or hollow balls
They include structures like Buckminsterfullerene.
What was the first fullerene to be discovered?
Buckminsterfullerene (C60)
It is shaped like a hollow sphere.
What shapes can carbon atoms form in fullerenes?
Carbon atoms can form hexagons, pentagons (five carbon atoms), or heptagons (seven carbon atoms)
This versatility contributes to the structure of fullerenes.
What are some applications of fullerenes?
Fullerenes can be used to deliver drugs and as catalysts
They can also form nanotubes, which have various uses.
What are nanotubes?
Nanotubes are tiny carbon cylinders
They have a high length-to-diameter ratio.
What is nanotechnology?
Technology that uses very small particles
Nanotubes are an example of materials utilized in nanotechnology.
What properties do nanotubes have that make them useful?
Nanotubes are useful in electronics and can strengthen materials without adding much weight
This makes them valuable in various applications.
Describe the structure and bonding of graphite.
Graphite consists of layers of hexagonal carbon atoms with three covalent bonds per atom
The lack of bonds between layers allows for sliding, making graphite soft.
What is metallic bonding?
Metallic bonding involves delocalised electrons that are shared among metal atoms, creating strong electrostatic attractions between positive metal ions and negative electrons.
Metallic bonds hold atoms together in a regular pattern, forming giant structures of metal atoms.
What are the characteristics of metallic bonds?
Metallic bonds are very strong and require lots of energy to break, leading to high melting and boiling points.
Most substances with metallic bonds are solids at room temperature.
What property of metals allows them to conduct electricity and heat?
The delocalised electrons in metals are free to move and can carry electrical charge and thermal energy.
This property makes metals good conductors.
What happens to the layers of atoms in a metal?
The layers of atoms in a metal can slide over each other, allowing metals to be bent or formed into different shapes.
This is due to the nature of metallic bonding.
What is an alloy?
An alloy is a mixture of two or more metals or a metal and another element.
Most metals used are alloys rather than pure metals.
Why are alloys harder and more useful than pure metals?
Mixing another element with a pure metal causes the layers of metal atoms to lose their shape, making it more difficult for atoms to slide over each other.
This increased difficulty in movement contributes to the hardness of alloys.
Fill in the blank: Metallic bonding involves _______ electrons.
delocalised
True or False: Pure metals are usually very hard.
False
Pure metals are often quite soft.
What energy is needed to break metallic bonds?
Lots of energy due to the strength of metallic bonds.
This results in high melting and boiling points for metallic substances.
Copper is a metal. What property allows it to be used in electrical circuits?
Its ability to conduct electricity due to delocalised electrons.
This property is common among metals.
Suggest why an alloy of copper is preferred over pure copper for making hinges.
An alloy is harder and more durable, preventing deformation under stress.
Hardness and durability are critical for practical applications like door hinges.
What are the three states of matter?
Solid, Liquid, Gas
What does particle theory explain about solids, liquids, and gases?
It explains how the particles in solids, liquids, and gases behave.
In solids, how are the particles arranged?
Particles are held close together in fixed positions to form a pattern.
What are the characteristics of solids?
Fixed shape and volume
What type of forces exist between particles in liquids?
Weak forces of attraction
How are particles arranged in liquids?
Randomly arranged and free to move past each other
What is the volume and shape characteristic of liquids?
Fixed volume but no fixed shape
What are the characteristics of gases?
No fixed shape or volume, particles are spaced far apart and travel in straight lines
What type of forces exist between particles in gases?
Very weak forces of attraction
What does ‘gaseous’ mean?
It means that it is a gas
What do state symbols indicate in a chemical equation?
They indicate whether a substance is a solid, liquid, gas, or aqueous.
What is the state symbol for solid?
(s)
What is the state symbol for liquid?
(l)
What is the state symbol for gas?
(g)
What does ‘aqueous’ mean?
Dissolved in water
Fill in the blank: In solids, there are ______ forces of attraction between particles.
strong
Fill in the blank: Gases will always fill ______.
containers
True or False: Liquids have a fixed shape.
False
What is a key difference between the arrangement of particles in solids versus liquids?
Solids have fixed positions, while liquids are randomly arranged and can move past each other.
What happens to the shape of liquids when placed in a container?
They flow to fill the bottom of the container.
What does the equation 2HCl(aq) + CaCO3(s) → CaCl2(aq) + H2O(l) + CO2(g) illustrate?
It illustrates a chemical reaction with state symbols indicating the states of the substances.
What happens to the particles of a solid when it is heated?
The particles gain energy and start to move about.
What is the temperature called at which a solid turns into a liquid?
Melting point.
What is the process called when a solid turns into a liquid?
Melting.
What happens to a liquid when it is heated?
The particles get even more energy, and the forces holding the liquid together weaken and break.
What is the temperature called at which a liquid turns into a gas?
Boiling point.
What is the process called when a liquid turns into a gas?
Boiling.
What happens to gas particles as they cool?
The particles have less energy, and forces form between them.
What is the process called when a gas turns into a liquid?
Condensing.
What happens to a liquid when it cools?
The particles have less energy, move around less, and the forces between them become stronger.
What is the process called when a liquid turns into a solid?
Freezing.
What determines the amount of energy needed for a substance to change state?
How strong the forces between particles are.
True or False: The stronger the forces between particles, the higher the melting and boiling points.
True.
What can you predict about the state of a substance at a certain temperature?
You can predict what state it is in based on its melting and boiling points.
If the temperature is below the melting point of a substance, what state is it in?
Solid.
If the temperature is above the boiling point of a substance, what state is it in?
Gas.
If the temperature is between the melting and boiling points, what state is the substance in?
Liquid.
What do bulk properties like melting point depend on?
How lots of atoms interact together.
Which substance is a liquid at room temperature (25 °C) from the following options: oxygen, nitrogen, bromine?
Bromine.
At what temperature does bromine melt?
-7 °C.
At what temperature does bromine boil?
59 °C.
What state is ethanol in at 0 °C if its melting point is -114 °C and boiling point is 78 °C?
Liquid.
What state is ethanol in at 25 °C if its melting point is -114 °C and boiling point is 78 °C?
Liquid.
What state is ethanol in at 100 °C if its melting point is -114 °C and boiling point is 78 °C?
Gas.
