Atomic structure and periodic table

Cards (55)

  • What is an isotope?
    Atoms of the same element that have different numbers of neutrons
  • What is a compound?

    two or more elements chemically bonded together
  • What does paper chromatography do ?
    Separates substances in a mixture
  • What is a mixture?
    A combination of two or more substances that have no chemical bond
  • What does filtration separate?
    Insoluble solids from liquids
  • What does distillation separate?
    A soluble slid and a liquid
  • Who described atoms as solid spheres?
    John Dalton
  • What did the different spheres represent
    Different elements
  • Who discovered electrons
    JJ Thomson
  • What was his mode of the atom called
    Plum pudding model
  • Describe the plum pudding model
    the atom is a ball of positive charge with negative electrons embedded in it
  • Who showed the plum pudding model was wrong
    Rutherford
  • What experiment did Rutherford do?
    Alpha particle scattering
  • What happened in this experiment
    They fired alpha particles at an extremely thin sheet of gold
  • What did they expect to happen
    The particles were expected to pass straight thorough or be slightly deflected at most
  • Why did they expect this
    The positive charge of each atom was thought to be very spread out
  • Wha actually happened

    Most particles passes straight through
    Some were deflected more than expected
    A small number were deflected backwards
  • Why did they pass through
    Most of the atom is empty space
  • Why were some deflected
    Alpha particles came near the concentrated positively charged nucleus
  • Why were some deflected backwards
    They were fired directly a the nucleus
  • What model of the atom did Rutherford come up with
    Nuclear model
  • Describe the nuclear model
    Tiny positively charged nucleus at the centre
    A cloud of negative electrons surrounded the nucleus
  • What did Bohr discover?
    Electron shells
  • Who discovered protons
    James Chadwick
  • Describe the periodic table in the early 1800s
    Electrons were arranged by atomic mass
    Some elements were laced in the wrong group
  • How did Mendeleev organize his periodic table?
    Mainly in order of atomic mass
    Grouped elements with similar properties
    Left gaps for undiscovered elements
  • How is the modern periodic table arranged
    Increasing proton number
    Elements with similar properties are in groups
  • What is a metal
    Elements that can form positive ions when the react
  • What's a non metal
    An element that doesn't generally form positive ions when it rects
  • Properties of meals
    Strong
    Malleable
    Good conductors (heat and electricity)
    High boiling and melting points
  • Properties of non metals
    Dull
    Brittle
    Poor conductors
    Lower density
  • What are the different properties of a transition metal

    Can have more than one ion
    Their ions are often coloured
    Transition metal compounds often make good catalysts
  • What are group 1 metals called
    Alkali metals
  • What are their properties
    Soft and have low density
  • What are the trends as you go down the group(group 1)

    INCREASING reactivity
    LOWER melting and boiling points
    HIGHER relative atomic mass
  • Reaction with water
    They read vigorously to produce HYDROGEN GAS and METAL HYDROXIDES
    Amount of energy released by the reaction INCREASES down the group
  • Reaction with chlorine
    When heated in chlorine gas they form WHITE METAL CHLORIDE SALTS
  • Reaction with oxygen
    Form a metal oxide
  • Why do they tarnish in the air
    Metal reacts with oxygen to form a dull metal oxide layer
  • Why are they called alkali metals
    The hydroxides the produce in water dissolve to produce alkaline solutions