Topic 1 - Atomic structure and periodic table

• What is an atom?

  The smallest part of an element
• What is an element?

  A substance of only one type of atom
• How are elements listed and how many are there approximately?

  Listed in the periodic table; approximately 100
• What are the two groups elements can be classified into based on their properties?

  Metals and non-metals
• What are new substances formed when elements combine through chemical reactions called?

  Compounds
• What is a compound?

  Two or more elements combined chemically
• Do compounds have the same properties as their constituent elements?

  No, they have different properties
• What is a mixture and does it have the same chemical properties as its constituent materials?

  A mixture consists of elements or compounds not chemically combined; it has the same properties
• What are the five methods through which mixtures can be separated?

  Filtration, crystallisation, distillation, chromatography
• Do the methods of separating mixtures involve chemical reactions?

  No, they do not involve chemical reactions
• What is a separating funnel?

  An apparatus for separating immiscible liquids
• How do two immiscible liquids behave in a separatory funnel?

  They form two distinct layers
• What happens to the bottom layer in a separatory funnel?

  It can be run off to a separate vessel
• Describe the plum-pudding model of the atom.

  The atom is a ball of positive charge with electrons embedded
• What does the Bohr/nuclear model suggest about electrons?

  Electrons orbit the nucleus at specific distances
• How did the Bohr model come about?

  From the alpha scattering experiments
• What are the smaller positive particles discovered in the nucleus called?

  Protons
• What did James Chadwick's work provide evidence for?

  The existence of neutrons in the nucleus
• Describe the structure of an atom.

  It has a small central nucleus with electrons around
• What are the relative masses and charges of protons, neutrons, and electrons?

  Masses: 1, 1, very small; Charges: 1, 0, -1
• Why are atoms electrically neutral?

  They have the same number of electrons and protons
• What is the radius of an atom?

  0.1 nm
• What is the radius of a nucleus compared to that of an atom?

  1 x 10$^{-14}$ m and 1/10000
• What is the name 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 an atom's mass located?

  In the nucleus
• What is the mass number?

  The total number of protons and neutrons
• How do you calculate the number of neutrons using mass number and atomic number?

  Subtract the atomic number from the mass number
• What is an isotope?

  Atoms of the same element with different neutrons
• Do isotopes of a certain element have the same chemical properties?

  Yes, they have the same electronic structure
• What is the relative atomic mass?

  The average mass value of isotopes
• What are ions?

  Charged particles formed by losing or gaining electrons
• What is an example of a positive ion?

  Sodium ion, Na+
• Compare the properties of metals and non-metals.

  • Metals:
  • High boiling/melting point
  • Conduct heat and electricity
  • Shiny appearance
  • Malleable
  • High density
  • Basic oxides
  • Non-metals:
  • Low boiling/melting point
  • Don’t conduct heat/electricity (except graphite)
  • Dull appearance
  • Brittle
  • Low density
  • Acidic oxides
• What is formed when a metal reacts with a non-metal?

  An ionic compound made of ions
• What is formed when a non-metal reacts with a non-metal?

  A molecular compound with covalently bonded atoms
• Explain the terms: solute, solvent, solution, miscible, immiscible, soluble, insoluble.

  • Solute: Substance dissolved in a solvent
  • Solvent: Substance that dissolves the solute
  • Solution: Mixture of solute and solvent
  • Miscible: Liquids that mix together
  • Immiscible: Liquids that do not mix
  • Soluble: Substance that can dissolve
  • Insoluble: Substance that cannot dissolve
• What are the columns of the periodic table called?

  Groups
• What are the rows of the periodic table called?

  Periods
• Are elements in the same group similar or different?

  They may have similar chemical properties