Summer Assessment 3 Flashcards
what is the mass number the total of
Number of protons and neutrons
how do you find out the number of neutrons
-subtract atomic number from mass number
what is the Atomic Number
Number of protons
what are molecules
-groups of atoms
what is a group in the periodic table
-what do elements in the same group have in common
- Vertical column in the Periodic Table
- All elements in the same group have the same number of outer shell electrons and similar chemical properties.
meaning of inert
Unreactive
what are periods in a periodic table
-Horizontal row in the Periodic Table
what group are the noble gases in
Group 0
give 2 properties of the noble gases
- inert
- colourless gases
why are the noble gases unreactive
-don’t have a full outer shell of electrons so arent desperate to give up/ gain electrons
what are ionic compounds made up of
-a positively charged part and a negatively charged part
name 5 properties of compounds with a giant ionic structure
- always have giant ionic structure
- ions held in closely packed 3D lattice arrangement
- electrostatic attraction between oppositely charged ions is very strong
- due to lots of energy needed to overcome the strong attraction- high melting and boiling point
- not electrical conductors when solid but are if melted/ dissolved in water
name properties of a simple molecular substance
- atoms within molecule held together by very strong covalent bonds
- the forces of attraction between molecules = very weak
- this results in a low melting and boiling point as molecules are easily spereated
- most are gases or liquids at room temperature
what happens to the melting and boiling point of simple molecular substances when the relative molecular mass increases
melting and boiling point increases as relative molecular mass increases
name 4 properties of a giant covalent structure
- atoms are bonded to each other by strong covalent bonds
- lots of these bonds- lots of energy to break them- high melting and boiling point
- don’t conduct electricity- not even when molten`
- usually insoluble in water
name the properties of diamond
- its made up of a network of carbon atoms that each form 4 fcovalent bonds
- strong covalent bonds take lots of energy to break so diamond has high melting point
- strong covalent bonds hold atoms in very rigid lattic structure so its really hard
- doesnt conduct electricity as it has no free electrons or ions
name the properties of graphite
- each carbon atom only forms 3 covalent bonds creating layers of carbon atoms
- layers are held together by weak intermolecular forces of attraction- so can slide over each other- making graphite soft and slippery
- high melting point- covalent bonds in layers need lots of energy to break
- graphite has one delocalised electrong which is free to move- so it can conduct electricity
briefly name the properties of diamond
- hard
- high melting point
- high boiling point
- cant conduct electricity
briefly name the properties of graphite
- soft and slippery
- high melting point
- conducts electricity
name the properties of C60 fullerene
- made up of large covalent molecules
- molecules held together by intermolecular forces that can slide over each other- hence why material is soft
- each carbon in C60 fullerene has a delocalised electron- however electrons cannot move between molecules so C60 fullerene is a poor conductor of electricity
briefly name the properties of C60 fullerene
- soft
- poor conductor of electricity
what is electric current and what does it cause to occur
- electric current = flow of electrons or ions
- when electrons/ ions move they cause material they are in to conduct electricity
why can ionic compounds only conduct electricity when molten or in solution
- as solid ionic compounds dont conduct electricity as ions cannot move around
- however when ionic compounds are dissolved, ions are seperate and able to move so can conduct electricity
- when ionic compound melts- ions are able to move- so ions can conduct electricity
what are metals held together by
-metallic bonding
how are metals arranged
-have a giant structure of positive ions surrounded by a sea of delocalised electrons
what is metallic bonding
the electrostatic attraction between the positive ions and the electrons
why are metals good conductirs of heat
movement of electrons means energy can be transferred quickly through the material so metals are good conductors of heat
why are metals good conductors of electricity
-as delocalised electrons are free to move through the structure- hence why metals can conduct electricity
why are most metals malleable
-layers of ions in a metal can slide over each other- making metals malleable
what do iron, aluminium and copper all have in common
- they are dense and lustrous (shiny)
- have high melting points
- have high tensile strength (strong and hard to break)
- malleable
- good conductors of electricity and heat
what are the uses of iron
-its malleable- so used to make gates and railings
what are the uses of aluminium
- doesn’t corrode- sp useful for products that come into contact with water (drink cans)
- much less dense than iron, so its lighter- useful for when the weight of the metal is important (bicycle frames and aeroplanes)
what are the uses of copper
- good conductor of electricity- used in electrical components- so is efficient at transferring electricity
- good conductor of heat- used in heating systems- allows speedy transfer of heat to surroundings
-what properties do pure metals have that aren’t always needed
-they are soft
-
are nitrates soluble or insoluble
-soluble
are common slats of potassium, sodium and ammonium soluble or insoluble
-soluble
are common chloride soluble or insoluble
- soluble
- except for silver chloride and lead chloride
are common sulfates soluble or insoluble
- soluble
- except for lead, barium and calcium sulfates
are common carbonates soluble or insoluble
- insoluble
- except for sodium, potassium and ammonium carbonates
are common hydroxides soluble or insoluble
- insoluble
- except for sodium, potassium and calcium hydroxides
how do you make an insoluble salt
- use a preceipitation reaction
- react 2 soluble salts together to get an insoluble salt
how do you make insoluble salt- lead nitrate
-add 1 spatula of lead nitrate to test tube
–add deionised water to dissolve it & shake thoroughly until its all dissolved
- in seperate test tube do the same with magnesium sulfate
- then tip the 2 solutions into small beaker & stir so its all mixed- lead sulfate should precipitate out
- fold filter paper in a filter funnel & put into conical flask
- pour contents of beaker into filter paper
- swill out beaker with more deionised water & tip into filter paper
- rinse contents of filter paper with deionised water
- scrape lead sulfate onto fresh filter paper & leave to dry in an oven
