Chemistry Paper 1- Major Focus Of Exam Flashcards
Why do elements in the same group react similarly?/ have similar properties?
Same number of electrons in their outer shell
What did dalton arrange elements in?
Order of atomic weight
What did John newlandd arrange elements in and what else did he notice?
Order of atomic weight
Noticed elements reacted in a similar way and that properties of every eighth element seemed similiar
What law did John new lands propose?
Law of octaves
What was a problem with newlands proposed idea?
Elements were grouped together when they had totally different properties
Why was Mendeleevs periodic table widely accepted?
Switched order of elements so they fitted the patterns of other elements in the same group
Left gals for undiscovered elements and predicted their properties
Are noble gases reactive or unreactive?
Unreactive
Why are nobles gases unreactive?
They have a full outer shell, so dknt need to react, so are stable
As the atomic masses of noble gases increases, what happens to their boiling point?
Increases
What groups of the periodic table contain highly reactive metals?
Group 1 and 2
When metals react, do they gain or lose electron to gain a full
Outer shell?
Lose
What type of ions do
Metals always form?
Positive ions
Are group 1 metals hard?
No, they are soft
Describe the trend of reactivity down group 1
Increases as you go down
Why does reactivity increase as you go down group 1?
Atoms get larger
Outer electron is further from nucleus
Attraction is weaker
Electron is more easily lost
What does the group number correspond to?
Number of electrons in outer shell
Do the melting and boiling points increase or decreases as we move down group 7?
Increase
What compounds do group 7 elements from when they react with non metals?
Covalent
When group 7 elements react with metal atoms, what type of compound do they form?
Ionic compoinds
What’s the trend of reactivity down group 7?
Decreases
Why does reactivity decrease as you go down group 7?
Atoms get larger
Outer shell get further from nucleus
Ability for nucleus to attract extra electron gets weaker
An extra electron is less easily attracted
When sodium is out in a gas jar of chlorine, what happens before/during/ after reaction
Before- yellow flame
During- white smoke
After- white solid
What are 2 reasons why in electrolysis, the mass of copper deposited was lower than the expected value?
Diff concentration of solution
Different current
Describe the observations/ what happens when lithium reacts with oxygen
Burn with a crimson flame
What happens when lithium reacts with water?
Floats on surface and release hydrogen as bubbles
What type of flame does sodium burn with when it reacts with oxygen?
Yellow
What happens when sodium reacts with water?
Floats on surface, releasing heat to melt the sodium, so it moves quickly across the surface
What happens when potassium reacts with water?
Similar to sodium but more vigourous
What is formed when alkali metals react with chlorine?
Metal chloride
Describe what happens when an alkali metal reacts with chlorine
Metal chloride is formed and dissolved in water to give a colourless solution
What are some differences with transition metals compared to alkali metals?
Transition: Higher density Lower reactivity Harder High melting points
What are 3 specials properties of transition metals?
Form ions with different charges
Form different colour compounds
Used as catalysts
Give one use of transition metals(beside as catalysts) and explain why they are used
Used in cooking equipment due to their high melting point
Why is graphite a good electrical conductor?
Contains 1 delocalised electron per carbon atom
It’s free to move to carry a charge
Why is graphite soft and slippery?
No bonds between layers
Made of weak intermolecular forces
Layers Can slide over each other
How can you find the total mass of copper produced?
Filter mixture
Wash and dry copper
Weigh copper collected
Add to increase in mass of electrode
State some potential improvements for the titration practical
Add acid dropwise
White tile under flask
Swirl solution
Which one of 0.1mil/dm3 or 1.0 mol/dm3 solution has a lower ph
1.0 mol/dm3
What’s the difference between the processes in electrolysis and in a chemical cell?
Electrolysis uses electricity to produce a chemical reaction whereas a chemical cell uses a chemical reaction to produce electricity
What are 2 properties of small covalent molecules?
Low melting/boiling points
Cannot conduct electricity
Why do small covalent molecules have low melting and boiling points?
Weak intermolecular forces
Require little energy to break
Why don’t small covalent molecules conduct electricity?
Molecules don’t have an overall charge
Why are giant covalent molecules always solid at room temperature?
Have strong covalent bonds
What element is diamond formed from?
Carbon
In diamond what does the carbon atom do?
Each carbon atom forms 4 covalent bonds to 4 other carbon atoms
Why does diamond have high melting and boiling points?
Main if of millions of carbon atoms bonded by strong covalent bonds
Requires lots of energy to be broken
Why can’t diamond conduct electricity?
No free electrons to carry a charge
What’s some properties of graphite?
High melting point
Soft and slippery
Conducts heat and electricity
In graphite what does each carbon atom form?
3 covalent bonds
In graphite, what do the carbon atoms form?
Hexagonal rings
Why is graphite slippery?
Hexagonal rings are in layers
No covalent bonds between layers
Layers can slide
Why can graphite conduct electricity?
Contains one delocalised electron
They can move and carry a charge
What is graphene?
Single layer of graphite
Is it true graphene is one atom thick?
Yes
Why is graphene an excellent conductor of electricity?
Has delocalised electrons
They can move and carry and a charge
Besides conducting electricity what’s another property of graphene?
Extremely strong
What are fullerenes?
Molecules of carbon atoms with hollow shapes
What shape is a buckminsterfullerene?
Spherical
What are used of fullerenes?
Used as lubricants
Drug delivery
Catalyst
What’s some properties of carbon nanotubes ?
Easily stretched
Conduct electricity and heat
What are polymers?
Very large molecules
What type of bonds do polymers contain?
Single covalent
Why are most polymers solids at room temperature?
Intermolecular forces are strong
Require lots of energy to be broken
Describe the bonding in metals
Consist of giant structure of atoms arranged in regular layers
Electrons in outer energy level is delocalised
Strong electrostatic attraction between sea of delocalised electrons and positive metal ions
Why are metallic bonds strong?
Strong electrostatic attraction between sea of delocalised electrons and positive metal ions
Why can metals be bent and shaped?
Layers of atoms can slide over each ither
Why are alloys harder than pure metals?
Different sizes of atoms distorts layers, making it more difficult for them to slide
What’s an advantage of a dot and cross diagram
Clear where electrons are coming from because we use dots and crosses
Why are disadvantages of using a dot and cross diagram?
Don’t tell us shape of molecule
What’s some disadvantages of a 2D stick model?
Can’t tell which electron in bind came from which atom
Give no idea of outer electrons that aren’t in bonds
Don’t give accurate information if shape of molecule
What’s a benefit if a 3D stick diagram?
Show shape of molecule
Benefit if ball and stick diagram
Can see ions in 3D
Disadvantage of ball and stick diagram
Show ions are spaced apart but in reality they are packed together
Benefit if spaced filling diagrams
See how closely packed ions are
Disadvantage of spaced filling diagram
Difficult to see 3D
Only show tiny part of lattice
