C3- Structure And Bonding Flashcards
Elements react together to form compounds by gaining or losing electrons or by _________ electrons
Sharing
How are ionic compounds held together?
By strong forces of attraction between thie roppositely charged ions
A solid turns into a liquid at its __________
Melting point
The hotter the gass is the _______ the particles move
Faster
What is the pressure of a gas caused by?
The particles colliding with the sides of the container.
The more frequent and energetic the collisions, thr higher thr pressure of gas.
In a sealed container the pressure of gas_____ with temperature
Increases
The hotter the solid is, the ____ its particles vibrate
Faster
Liquid turns to gas at ________ point
Boiling
As the _________ rises, more and more energy is transferred from the sorroundings to the particles and the particles escape from the surface of the liquid,
the rate of evaporation increases.
Temperature
___________ are formed in changes of state
No new substances
What affects the arrangements of particles?
The temperature
When you monitor the temperature of a soild as you heat it beyond its melting point what happens?
The temperature stops rising at the solid’s melting point.
- the tempurature remains constant until the solid has melted
- only then the tempurature starts to rise again
What happens at a solids melting point?
Enougg energy is transferred from the surroundings to the solid for the forces between particles in the solid to break.
-this enables particles to break away from their fixed positions and start moving around
What does the simple particle model show?
Particles are made up of solid spheres with no forces operating between them
What is the particle model useful for?
Comparing the properties of solids, liquids and gases.
In melting and boiling, energy is transferred from the _______ to the ________
- Surroundings
2. Substance
In freezing and condensing energy is transferred from the _______ to the ________
- Substance
2. Surroundings
What does a compound contain?
Two or more elements that are chemically combined
The noble gases have an arrangement of electrons that make them__.
Stable
What is ionic bonding?
Transferring electrons
What is covalent bonding?
Sharing electrons
You lose electrons to form____
Positive ions
You gain electrons to form?
Negative ions
Metal atom which tend to _____ electrons react with non-metal atoms which tend to _______ electrons
- Lose
2. Gain
How can you show transferred electrons?
Dot and cross diagram
Elements in group _ react with elements in group _
1
7
Why do elements want to lose/gain electrons?
To get a stable electronic structure
A compound will have the same electronic structure as a noble gas
How are ionic compounds usually formed?
When metals react with non-metals
In this the metals form positive ions and the non-metals form negative ions
Ions formed are held next to each other are held by_________
Very strong forces of attraction between the oppositely charged ions
The electrostatic force of attraction which acts in all directions is called?
Ionic bonding
What ions do Group 1 atoms form?
1+ ions
What do group 7 atoms form?
1- ions
Besides the elements in Group 1 and Group 7 that can form ionic compounds include______
Those in Group 2 (forming 2+ ions)
Those in Group 6(forming 2- ions)
It takes a lot of energy to break up a ___________
Giant ionic lattice
Why do ionic compoundd have a high melting point?
Because to seperate the ions you have to overcome all the elecrtostatic forces of attraction acting in all directions.
What are ionic metals as liquids attracted to?
Oppositely charged electrodes held in the molten compound.
Can a soild ionic compound conduct electricity, explain why.
No beacuse its ions afe held in foxes positions in the lattice
Do ionic compounds dissolve in water?
Most but not all
Do ionic compounds dissolved in water conduct electricity?
Yes because the ions are able to move to an oppositely charged electrode dipped in the solution
Does molten ionic compounds conduct electricity?
Yes
Simple: why can ionic compounds conduct electricity when molten or dissolved in water?
Because their ions can become mobile and carry charge through the liquid
What do reactions between metals and non-metals usually result in?
Ionic bonding
Non-metals react together, their atoms shair pairs of electrons to for, molecules. What is this called?
Covalent bonding
The atoms of non-metals tend to ____ electrons to achieve stable electron structures
Gain
What are covalent bonds?
When the atoms in the molecules are held together by shared pairs of electrons.- the strong bonds between the atoms are called covalent bonds
How can you show covalent bonds in substances such as water?
- the number of covalent bonds
- the highest energy levels(outer shells)
- the outer electrons in dot and cross diagram
What are giant covalent structures sometimes referred to as?
Macromolecules
Does Diamond have a giant covalent structure?
Yes
Describe diamond’s giant covalent structure:
Each carbon atoms forms four covalent bonds with its neighbours. -it results ina rigid giant covalent structure lattice
How are covalent bonds formed?
When atoms of non-metals share pairs of electrons with each other
Each shared pair of electron is a ______
Covalent bond
Many substances containing covalent bonds consist of simple molecules but some have giant covalent structures
This is true 👍🏻
Are electrons in covalent bonds constantly moving?
Yes
In covalent bonds are the molecules held tightly together?
Yes
How big is the force of attraction between the individual molecules?
Small (weak intermolecular forces)
Why do larger molecules have higher melting and boiling points?
Because intermolecular forces increase with the size of the molecules.
Why can’t simple molecules conduct electricity
They have no overall charge so they cannot carry an electrical charge
Do substances made up of simple molecules have low melting points and boiling points?
Yes
What is the problems with using models?
Each one has its limitations in representing reality
What do Diamonds and other huge covalent structures have?
Huge networks of atoms arranged in simple molecules- the huge networks pf atoms are held together by strong covalent bonds in giant covalent structures
What are some examples of giant covalent structures?
Graphite
Silicon dioxide
Diamond
What are the properties of Giant covalent structures?
- high melting and boiling points
- insoluble in water (can’t dissolve in water)
- apart from graphite they are hard and do not conduct electricity
Im diamond how many covalent bonds does each atom form?
4
What is Graphite used in?
Pencil lead
How many carbon atoms is each carbon atom bonded to?
3
What ks there between layers in graphite?
Weak intermolecular forces(no covalent bonds)
Carbon has 4 atoms in its outer shell. If 3 are used in graphite what happens to the other one?
They move freely along the layers of carbon atoms.
The mobile elctrons in Graphite are called Delocalised electrons
How do delocalised elelctrons behave?
Like electrons in metallic structure
The delocalised electrons allow Graphite to ______
Conduct elelctricity
Why is Graphite a good conductor of thermal energy?
As more energy is transferred to the delocalised electrons, they move around faster and rapidly transfer the energy along the layers of the Graphite
As well as Diamond and graphite carbon also exaits as ________ which can form large cage-like structures and tubes based on hexagonal rings of carbon atoms
Fullerenes
How are fullerenes finding uses?
As transport mechinism for drugs to specific sites in the body, as catalysts and as a reinforcement for composite matierals
What are catalysts?
The process of increasing the rate of a chemical reaction without undergoing a chemical change itself
What is graphene?
A single layer of graphite one layer thick.
Properties: very good at conducting electricity and it will help create new developments in the electronic industry in the future.
What are Cylindrical fullerenes?
Very thin cylinders
- high tensile strength
- high electrical conductivity
You can see ____ crystals on the surface of some steel that has been dipped into molten ____ to prevent it
Zinc
Zinc
-this is called galvanised steel
Are the atoms in metals closely packed together and arranged in regular layers?
Yep
What is metallic bonding?
Positively charged electrons
-held together by electrons from the outermost shell of each metal atom. These delocalised electrons are free to move throughout the giant metallic littice
The ____ electrons from each metals atom can easily move throughout the giant structure
Outer
Why are the layers of metal in a pure atom able to slide over each other?
Because metals can be hammered and bent into diffrent shales and drawn out into wires
Atoms in a pure metal such as iron are held together by what?
A Giant metallic structure
In giant metallic structures the atoms are arranged closely in packed layers this allows them to do what?
It allows the atoms to slide over one and other easily
What is an alloy?
A mixture of two or more elelments, at least of one which is a metal
The positive ions in a metlas giant structure are binded together by______
A sea of delocaslised electrons
( they act almost like a glue- the negatively charged between the positively charged ions hold the the metal ion in position by electrostatic forces of attraction.)
Can delocalised electrons move throughout the whole lattice?
Yes
Are alloys harder than pure metals if so why?
Yes because the regular layers in a pure metal are distorted by atoms of diffrent sizes in an alloy
What allows electricity and thermal energy to be transferred through a metal easily?
Delocalised elelctrons
What group tend to become stable by sharing electeons(covalent bonding)
Group 4
How do you know if a compound is covalent or ionic?
ionic bond is between a metal and a nonmetal, and a covalent bond is between 2 nonmetals.
What is the line that represents covalent bonding in 2 florine atoms?
F-F
how do you know if something is a giant covalent structure, a giant ionic structure or a simple molecule?
If it is a gas, liquid or low melting point solid then you are talking about a simple molecular substance. … If it is a high melting point solid, it will be a giant structure - either ionic, metallic or giant covalent
What are giant metallic structures?
Metals are giant structures with metal ions arranged in a regular, repeating lattice with layers of metal ions.
Metallic bonding?
Positively charged metals ions with a sea of delocaslised electrons
What is metallic bonds
Electrostatic attraction in a metal
What is a giant ionic lattice
Strong electrostatic forces of attraction acting in all directions between the oppositely charged ions
