GCSE AQA science Chemistry Flashcards

• Draw and label an atom

  Protons

  Neutrons

  Electrons

  
• What are the masses and charges of these parts of an atom?

  
  

  • Proton

  • Neutron

  • Electron


  Protons = +ve

  (mass 1)

  
  

  Neutrons = neutral

  (mass 1)

  
  

  Electrons = -ve

  (mass 1/2000th)
• Why do atoms usually have no overall electrical charge?

  Atoms usually have no overall charge because they have equal numbers of protons (+ve) and electrons (-ve), which cancel one another out
• All atoms of a particular element (e.g. carbon) all have the same number of what?

  Protons
• What does relative atomic mass tell you about the atom?


  The number of protons and neutrons in the atom
• What does atomic number tell you about the atom?

  The number of protons (usually the same as the number of electrons)
• What is an isotope?

  An isotope is an atom with a different amount of neutrons
• How many electrons can occupy the 1st and 2nd shell (energy level) of an atom?

  2 in the 1st shell and 8 in the 2nd shell
• The electron structure of sodium can be represented as 2,8,1 - what does this mean?

  
  

  Represent these atoms: -

  • Fluorine

  • Oxygen

  • Potassium

  • Magnesium


  2,8,1 means 2 electrons in the 1st shell, 8 electrons in the 2nd shell and 1 electron in the 3rd shell

  
  

  Fluorine = 2,7

  
  

  Oxygen = 2,6

  
  

  Potassium = 2,8,8,1

  
  

  Magnesium = 2,8,2
• Define these terms: -

  
  

  • Element

  • Compound

  • Mixture


  Element - a pure substance made from 1 type of atom only

  
  

  Compound - 2 or more elements chemically bound

  
  

  Mixture - 2 or more elements or compounds mixed together which are not chemically bound
• What happens to the electrons of 2 atoms when they chemically react?

  During a chemical reaction electrons are either given away, taken, or shared
• What is an ion?

  
  

  How are +ve ions formed?

  
  

  How are -ve ions formed?

  An ion is an atom with a charge

  
  

  +ve ions have lost electrons

  
  

  -ve ions have gained electrons
• Explain how the following atoms become ions (will they be +ve or -ve)?

  
  

  • Potassium

  • Magnesium

  • Chlorine

  • Oxygen

  Potassium - loses 1 electron (K+)

  
  

  Magnesium - loses 2 electrons (Mg2+)

  
  

  Chlorine - gains 1 electron (Cl-)

  
  

  Oxygen - gains 2 electrons (O2-)

  
• Describe the structure of ionic compounds

  Ionic compounds have a giant structure - they are bonded to 6 other ions by electrostatic bonds
• What are the melting and boiling points of ionic compounds like?

  
  

  Why is this?

  Ionic compounds have high melting points and boiling points - to melt them you have to supply enough energy to break the 6 bonds attached to each ion
• What happens to the electrons when atoms form ionic bonds and covalent bonds?

  
  

  Which is the strongest?

  Ionic bonds - 1 atom loses electrons and another gains electrons

  
  

  Covalent bonds - electrons are shared

  
  

  An individual covalent bond is stronger than an ionic bond
• What are the melting and boiling points of covalent compounds like?

  
  

  Explain why this is

  Covalent compounds have low melting and boiling points (are often gases) are there is no attraction between the molecules
• How are the elements of the periodic table arranged?

  
  

  What are the rows called?

  
  

  What are the columns called?


  Elements are arranged in order of atomic number

  
  

  Rows are called periods

  
  

  Columns are called groups
• Which 2 elements would be out of order in the periodic table if they were arranged by atomic mass instead of atomic number?

  Potassium and Argon
• Why do elements in the same group have similar properties?

  Elements in the same group have similar properties as they all have the same number of electrons in their outer shell
• What do these symbols mean?

  
  

  • (s)

  • (l)

  • (g)

  • (aq)


  (s) = solid

  (l) = liquid

  (g) = gas

  (aq) = aqueous
• What are the symbols for these compounds?

  
  

  • Calcium carbonate

  • Sodium chloride

  • Hydrochloric acid


  Calcium carbonate - CaCO3

  
  

  Sodium chloride - NaCl

  
  

  Hydrochloric acid - HCl
• Why do covalent compounds not conduct electricity when dissolved?

  Covalent compounds do not conduct because they do no break down into ions
• Give the names of 3 covalent compounds which have giant ionic structures?

  
  

  What is the structure of each like?

  Diamond - 4 carbon-carbon covalent bonds

  
  

  Graphite - 3 carbon-carbon covalent bonds

  
  

  Silicon dioxide - 2 double silicon-oxygen covalent bonds
• Why does graphite conduct electricity?

  Graphite conducts electricity because it is only bonded 3x (meaning there is a delocalised electron to pass the charge)
• Explain why ionic compounds have a giant structure

  Ionic compounds have giant structures because the ions keep their charge and attract up to 6 other ions - forming a giant lattice
• What does monatomic mean and why are noble gases monatomic?


  Monatomic means an atom which only exists on its own (does not react)

  
  

  Noble gases are monatomic as they have a full shell and are un-reactive
• What does diatomic mean and why are elements such as the halogens, hydrogen and oxygen diatomic?

  Diatomic - atoms in pairs, e.g. H2 and O2

  
  

  Halogens will form diatomic molecules because they covalently bond with each other, forming pairs
• What is the bonding in metals like?

  The bonding in metals creates delocalised electrons (free to move and pass on electrical current)
• Why do metals conduct electricity?

  The bonding in metals creates delocalised electrons (free to move and pass on electrical current)
• Why do ionic compounds conduct electricity when they are dissolved / molten?

  Ionic compounds conduct electricity when dissolved or molten because they remain as ions (which will pass a current)
• What are the symbols for these compounds?

  
  

  • Sulfuric acid

  • Sodium hydroxide

  • Nitric acid


  Sulfuric acid = H2SO4

  
  

  Sodium hydroxide = NaOH

  
  

  Nitric acid = HNO3
• What are the symbols for these compounds?

  
  

  • Magnesium oxide

  • Ammonia

  • Methane

  Magnesium oxide = MgO

  
  

  Ammonia = NH3

  
  

  Methane = CH4
• Which group of the periodic table do not form ions?

  
  

  Explain why this is

  Noble gases do not form ions as they already have a full outer shell
• What are the names of the following groups in the periodic table?

  
  

  • Group 1

  • Group 2

  • Middle metals

  • Group 7

  • Group 0


  Group 1 = alkali metals

  
  

  Group 2 = alkaline Earth metals

  
  

  Middle metals = transition metals

  
  

  Group 7 = halogens

  
  

  Group 0 = Nobel gases
• What are nano-materials and what are they used for?


  Nano-materials are very small (one nano-metre = one-thousand-millionth of a metre)

  
  

  They are used for self-cleaning coats on glass etc...
• What are smart materials and what are they used for?

  Smart materials return to their original shape, e.g. metals which can be stretched and then return to their original shape (metals used in braces / spectacles)
• What is a macromolecule?

  
  

  Give some examples

  Macromolecules - are formed by giant covalent bonds, e.g. diamond, graphite, silicon dioxide etc...
• What is the bonding like in diamonds?

  Each carbon atom forms 4 covalent carbon-carbon bonds with the carbons around them creating a giant structure and makes them very hard
• What is the bonding like in graphite?

  Each carbon forms 3 covalent carbon-carbon bonds with the carbons around them creating a sea of delocalised electrons which will pass an electrical current