Topic 1 - Atomic Structure and the Periodic Table

    Cards (62)

    • What is an atom?
      smallest part of an element
    • What is an element?
      substance of only one type of atom.
    • What is a compound?
      Two or more elements combined chemically in fixed positions
    • Do compounds have the same properties as their constituent elements?
      No, they have different properties.
    • What is a mixture? Does it have the same chemical properties as its constituent materials?
      two or more elements not chemically combined together; it does have the same chemical properties.
    • 5 methods through which mixtures can be separated. Do these involve chemical reactions?
      Filtration, crystallisation, simple distillation, fractional distillation and chromatography; they do not involve chemical reactions.
    • Describe and explain simple distillation.
      Simple distillation is used to separate liquid from a solution - the liquid boils off and condenses in the condenser. The thermometer will read the boiling point of the pure liquid. Contrary to evaporation, we get to keep the liquid.
    • Describe and explain evaporation
      Evaporation is a technique for separation of a solid dissolved in a solvent from a solvent.
      The solution is heated until all the solvent evaporates; the solid stays in the vessel
    • Describe and explain crystallisation
      Crystallisation is similar to evaporation, but we only remove some of the solvent by evaporation to form a saturated solution (the one where no more solid can be dissolved). Then, we cool down the solution. As we do it, the solid starts to crystallise, as it becomes less soluble at lower temperatures. The crystals can be collected and separated from the solvent via filtration.
    • Describe and explain fractional distillation
      Fractional distillation is a technique for separation of a mixture of liquids. it works when liquids have different boiling points.
      The apparatus is similar to the one of simple distillation apparatus, with the additional fractionating column placed on top of the heated flask.
      The fractionating column contains glass beads. It helps to separate the compounds. In industry, mixtures are repeatedly condensed and vaporised. The column is hot at the bottom and cold at the top. The liquids will condense at different heights of the column.
    • Describe and explain filtration
      Filtration is used to separate an insoluble solid is suspended in a liquid. The insoluble solid (called a residue) gets caught in the filter paper because the particles are too big to fit through the holes in the paper. The filtrate is the substance that comes through the filter paper. Apparatus: filter paper + funnel
    • Describe and explain chromatography
      Chromatography is used to separate a mixture of substances dissolved in a solvent.
      In paper chromatography, we place a piece of paper with a spot containing a mixture in a beaker with some solvent. The bottom of the paper has to be in contact with the solvent. The solvent level will slowly start to rise, thus separating the spot (mixture) into a few spots (components).
    • What is a separating funnel
      A separatory funnel is an apparatus for separating immiscible liquids. Two immiscible liquids of different densities will form two distinct layers in the separatory funnel.
      We can run off the bottom layer (the liquid with greater density) to a separate vessel.
    • Describe the plum pudding model
      The atom is a ball of positive charge with a negative electron embedded in it.
    • Describe the Bohr/nuclear model and how it came about
      The nuclear model suggests that electrons orbit the nucleus at specific distances (shells) - it came about from the alpha scattering experiments.
    • What did the work of James Chadwick provide evidence for?
      The existence of neutrons in the nucleus.
    • Describe the structure of an atom
      The atom has a small central nucleus (made up of protons and neutrons) around which there are electrons
    • State the relative masses and relative charges of the proton, neutron and electron.

      masses: 1 , 1 , very small
      charges: 1 , 0 , -1
    • What is the radius of an atom?
      0.1 nm
    • What name is given to the number of protons in the nucleus
      atomic number
    • Atoms of the same element have the same number of which particle in the nucleus?
      protons
    • Where is the majority of mass of an atom?
      The nucleus
    • What is the mass number?
      The total number of protons and neutrons
    • How does one calculate the number of neutrons using mass number and atomic number?
      Subtract the atomic number from the mass number
    • What is an isotope? Do isotopes of a certain element have the same chemical properties?
      Atoms of the same element (same proton number) that have a different number of neutrons
      They have the same chemical properties as they have the same electronic structure.
    • What is the relative atomic mass?
      The average mass value which takes the mass and abundance of isotopes of an element into account.
    • Give the electronic configurations of He (2), Be (4), F (9), Na (11), and Ca (20) to demonstrate how shells are occupied by electrons.
      2
      2,2
      2,7
      2,8,1
      2,8,8,2
    • What are ions
      Ions are charged particles. They are formed when atoms lose electrons (positive ions) or gain (negative ions) electrons.
    • What is formed when a metal reacts with a non-metal?
      An ionic compound (made of positive and negative ions)
    • What is formed when a non-metal reacts with a non-metal?
      A molecular compound containing covalently bonded atoms. Atoms share electrons, as opposed to transferring electrons between each other.
    • Explain the following: solute, solvent, solution, miscible, immiscible, soluble, insoluble.
      A solute is a substance that is dissolved in a solvent. Together they form a solution.
      Miscible refers to the substances (particularly liquids) that mix together, e.g. water and alcohol. Water and oil are immiscible, i.e they do not mix
      Soluble refers to the substance that can be dissolved in a solvent, e.g. salt in water. Insoluble substances will not dissolve in a particular solvent.
    • The columns of the periodic table are called?
      groups
    • The rows of the periodic table are called..?
      periods
    • Are elements in the same group similar or different?
      They may have similar chemical properties, as they have the same number of outer shell electrons.
    • In terms of energy levels, what are the differences between elements of the same period?
      They have the same number of energy levels
    • Electrons occupy particular energy levels, with each electron in an atom at a particular energy level; which available energy level do electrons occupy?
      The lowest available energy level.
    • The elements of Group 0 are more commonly known as..?
      The noble gases
    • What makes the periodic table periodic?
      Similar properties of elements occur at regular intervals.
    • Elements in the same group have the same number of electrons in their outer shell; what does this tell us about their chemical properties?
      They have similar chemical properties
    • In terms of shells, what is the difference between elements in the same period?
      they have a different number of shells