C1 atomic structure and the periodic table

• element definition

  all the atoms are the same
• compound definition

  contain 2 or more different elements chemically combined
• mixture definition

  different elements or compounds but not chemically combinded
• molecule definition

  has any element chemically combined even if they are the same
• what is filtration used for

  seperating insoluble solid from liquid
• what is crystallisation used for

  separating soluble solid from liquid
• what is fractional distillation

  used to separate different liquids with different boiling points
• what is the nuclear model

  atom is empty space with positive nucleus in centre containing most of mass with negative electrons in edge
• radius of an atom

  0.1 nanometers (1x10 ^-10)
• relative charge and mass of protons

  Charge - +1

  mass - 1
• relative charge and mass of neutron

  charge - 0

  mass - 1
• relative charge and relative mass of electron

  charge - -1

  mass - very small
• electron charge

  negative
• proton charge

  posotive
• neutron charge

  neutral
• what does atomic number (smaller number) tell us

  number of protons and electrons in element
• what does atomic mass number (bigger number) tell us

  TOTAL number of protons and neutrons
• isotopes meaning

  atoms of the same element with different number of neutrons
• what is an ion

  atom which has an overall charge because ions have lost or gained electrons
• electron configuration (max electrons in one shell)

  2,8,8,
• how did mendeleev discover the modern periodic table

  arranging all elements in increasing atomic mass

  left gaps for undiscovered elements
• difference between modern periodic table and Mendeleev's

  elemets are arranged in atomic number because protons not discovered during his time

  
  

  modern table has group 0
• why are group 0 atoms unreactive

  they have a full outer shell of electrons so it is stable
• second key feature of group 0

  boiling point increases as the relative atomic mass increase (going down)
• where are metals found in periodic table

  left and middle
• where are non metals found in periodic table

  right
• key feature about metals reacting

  when metals react they lose electrons to get full outer shell so element becomes stable

  
  

  always form positive ion
• how many electrons do group one metals have on their outer shell

  1
• group one reactivity features

  as you go down group one the quicker they react
• why do group one metals react quicker as you go down

  because outer electron is lost and elements at bottoms of group 1 lose it easier the top ones
• why does group 1 react more as you go down the ground

  
  

  as you go down outer electron if further away from nucleus - electrostatic attraction is weaker between negative electron and positive nucleus - so electron easily donated when bonding
• what is group 7 called

  the halogens
• how many electrons do group 7 have in they outer shell

  7
• what do group 7 non metals do to get full outer shell

  covelant bond to gain electron
• what happens as you go down group 7

  elements become less reactive as you go down group
• why does reactivity decrease as you go down group 7

  atoms become larger as you go down, leading to a weaker attraction between nucleus and outer electrons. weaker attraction makes it harder for atom to gain electron and being stable
• How does the reactivity of halogens change down group seven?

  It decreases as you move down