Paper 1 Flashcards
(44 cards)
What are the physical properties of most non-metals? (5)
- Brittle
- Dull
- Lower melting and boiling points
- Poor conductors of electricity
- Lower density
Why were elements often placed in the wrong group in early versions of the periodic table?
Elements were placed in order of atomic weight rather than atomic mass, and didn’‘t take into account the elements chemical properties
When balancing a chemical equation, are you allowed to change the small number?
No, you can only change the large numbers in front of each substance.
What is the benefit of using crystallisation rather than evaporation as a separating technique?
The excess heat used in evaporation can sometimes cause the crystals to break down by thermal decomposition
What is a simple molecular substance?
Substance that consists of small molecules
What is an alkali?
A base that dissolves in water to form a solution with a pH greater than 7
What is an ion?
An ion is a charged atom or molecule
Name 4 allotropes of solid carbon?
- Diamond
- Graphite
- Graphene
- Fullerenes
State the three trends in the group 7 elements as you go down the periodic table?
- Decreased reactivity
- Higher melting/boiling points
- Higher atomic mass
What is meant by an atoms ‘outer shell’?
The ‘outer shell’ is the shell of electrons that is furthest from the nucleus
What is the charge of proton?
Positive, 1 or +1
Describe how an ionic bonds form between a metal atom and a non-metal atom?
- The metal atom will transfer one or more electrons to the non-metal so that both have full outer shells.
- This will make the metal a positive ion, and the non-metal a negative ion.
- The two oppositely charged ions will be strongly attracted by electrostatic forces.
- This electrostatic attraction is called an ‘ionic bond’.
How can you use the atomic number and mass number of a given atom, to work out how many neutrons it has?
Number or neutrons = mass number - atomic number
What does ‘ductile’ mean?
Ductile means a structure can be drawn into wire.
What is a solution?
A solution is a mixture that contains a solute (the solid) dissolved in a solvent (the liquid)
In the electrolysis of molten aluminium oxide, are the Al3+ ions oxidised or reduced?
The Al3+ ions are reduced as they gain electrons.
What is the pH scale, and what are its minimum and maximum values?
The pH scale is a measure of how acidic or alkaline a solution is. It ranges from 0 (very acidic) to 14 (very alkaline).
State the 3 trends seen in group 1 metals as you go down the periodic table?
- Increased reactivity
- Lower melting and boiling points
- Higher atomic mass
What are the physical properties of a typical metal.
- Strong
- Malleable
- Ductile
- Good conductors of electricity and heat
- High melting and boiling points
- Dense
- Shiny
Why is aqueous electrolysis generally cheaper than molten electrolysis?
In aqueous electrolysis the substance is just dissolved in water, no energy is required to melt it.
In a chemical reaction, is there any change is the overall mass of the substances?
No. The overall mass of the products will be exactly the same as the overall mass of the reactants.
What is the charge of a neutron?
Neutral, or 0
Give 2 examples of endothermic reactions?
- Thermal decomposition
- Citric acid + sodium hydrogen carbonate
What are fullerenes?
Fullerenes are molecules of carbon atoms that exist as hollow shapes, such as spheres or cylinders.
