Key terms Flashcards

• What is the definition of a base?

  A substance which readily accepts H+ (hydrogen) ions usually given off from an acid
• What is the definition of an acid?

  A molecule that can dissociate and release a H+ (hydrogen) ions
• What is the definition of an alkali?

  A compound that produces OH- (hydroxide) ions when dissolved in water
• Electronegativity


  The power of an atom to attract the pair of electrons in a covalent bond
• Dative bond


  a covalent bond in which both electrons come from the same atom
• polar


  having a pair of equal and opposite charges
• London forces


  the weak attractive forces between molecules resulting from the small, instantaneous dipoles that occur because of the varying positions of the electrons during their motion about nuclei
• Atomic Orbitals/Shells


  A region around the nucleus that can hold up to 2 electrons with opposite spins
• Permanent dipole-dipole interactions

  Weak electrostatic forces of attraction between polar molecules
• hydrogen bond


  A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.
• oxidation number


  Positive or negative number that indicates how many electrons an atom has gained, lost, or shared to become stable
• reduction


  gain of electrons, decrease in oxidation number
• Oxidation

  loss of electrons, increase in oxidation number
• oxidation agent


  the substance that oxidizes another substance by accepting its electrons
• reduction agent


  the substance that reduces another substance by losing electrons
• shells


  the orbits of electrons around the nucleus in certain energy levels
• Energy level 1 holds how many electrons?

  2 electrons
• energy level 1 consists of which sub level

  S
• Energy level 2 holds how many electrons?

  8 electrons
• energy level 2 consists of which sub levels


  s and p
• Energy level 3 holds how many electrons?

  18 electrons
• energy level 3 consists of which sub levels


  s, p, d
• Energy level 4 holds how many electrons?

  32 electrons
• energy level 4 consists of which sub levels


  s, p, d, f
• atomic number


  the number of protons in the nucleus of an atom
• mass number


  the number of protons and neutrons in the nucleus of an atom
• Isotope

  Atoms of the same element that have different numbers of neutrons
• Relative isotopic mass (RIM)


  The mass of an atom of an isotope of an element relative to 1/12 the mass of an atom of carbon-12
• Reletive Atomic Mass (RAM)

  Weighted mean mass of an atom of an element compared with 1/12th mass of carbon-12
• Why are there no units for RIM or RAM

  No units since they are reletive
• mass spectrometry


  a technique that separates particles according to their mass
• What does it mean if a molecule is polar?

  It has uneven charge distribution in a molecule creating a positive and negative area, and it will dissolve in water.
• Dipole


  created by equal but opposite charges that are separated by a short distance
• Atom economy


  A measure of the amount of starting materials that end up as useful products
• Atom economy equation

  Mr of desired product/Mr of all products x100
• Percentage yield

  actual yield/theoretical yield x 100 (in moles)
• What does VSEPR stand for?

  Valence Shell Electron Pair Repulsion
• Do lone pairs or bonded pairs repel more?

  lone pairs
• Why are electrons pairs arranged as far as possible from each other?

  Minimises repulsion
• Definition of covalent bond


  The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms