OCR A level Chemistry Module 2

• What is the charge and mass of proton, electron and neutron?

  Proton: +1 charge, 1 atomic mass unit Electron: -1 charge, 0.0005 atomic mass unit Neutron: 0 charge, 1 atomic mass unit
• What are isotopes?

  Isotopes are atoms of the same element that have different numbers of neutrons but same number of protons. They have same chemical properties.
• What is mass number?

  The number of protons and neutrons.
• What is an ion?

  An atom with a positive or negative overall charge.
• What is the relative atomic mass unit (AMU)?

  The average mass of one atom of an element relative to one twelfth of the mass of a carbon-12 atom.
• What is the relative isotopic mass?

  Mass compared to 1/12 the mass of carbon twelve.
• How do you calculate relative atomic mass?

  1. Times each isotope by its percentage
  2. Add your answers from step 1 together
  3. Divide by 100
• What shape is the s and p sub level?

  S sublevel: Spherical P sublevel: Dumbbell
• How many orbitals are in each sub levels?

  S, P, D, F sublevels have 1, 3, 5, 7 orbitals respectively.
• What is the correct order of sub level energies?

  
• What is the Aufbau principle?


  Electrons occupy the lowest energy sublevels available.
• What is Pauli Exclusion Principle?


   An orbital can contain a maximum of two electrons.
• What is the maximum number of electrons in each sub level?

  s sublevel: 2

  p sublevel: 6

  d sublevel: 10
• What are Hund's rules?

  Orbitals in the same sublevel are singly occupied before they become doubly occupied. All electrons in singly occupied orbitals must have the same spin.
• Why is Hund's first rule true?

   Electrons in the same orbital repel each other more than electrons in different orbitals. And so electrons occupy different orbitals in the same sublevel to reduce repulsion. 
• Which substance’s electron configuration cannot be predicted by using a combination of the Aufbau principl, the Pauli exclusion principle and Hund’s rules?

  Cr and Cu and any ions formed in the 3d block as loses electrons from 4s sub shell first.

  
• A material made up of two or more types of repeating unit is called a mixture. A material made up of only one type of repeating unit is called a substance.
• A substance which contains atoms of two or more different elements is called a compound.
• What does the electron sea model state?

  States that a metal is made up of a  lattice of  cations or positive ions , surrounded by a ‘sea’ of delocalised electrons.
• What is metallic bonding?

  Metallic bonding is the electrostatic attraction between positively charged metal ions and delocalized electrons.
• How are metals malleable and ductile?

  Layers of cations can slide over each other without breaking the metallic bonding.
• Why do metals have stronger melting and boiling points?

  There is a strong attraction between cations and delocalised electrons
• Why down a group does the melting point of metals decrease?

  The distance between cations and delocalised electrons increases.
• What are the metals in the periodic table?

  ANSWER:

  
• What are alloys?


  Metals made from two or more elements.
• Why across a period does the melting point of metals increase?

  Greater charge and stronger metallic bonding.
• What is ionic bonding?


  The electrostatic attraction between oppositely charged ions.
• What is the list of common cations?

  ANSWER:

  
• What are the common anions?

  When they’re in an ionic compound: ​Group seven anions have a - charge. Group six anions have a 2- charge. Group five anions have a have a 3- charge.
• What is the charge of a carbonate ion?

  2-

  
• What is the charge of a sulfate ion?

  2-

  
• What is the charge of a nitrate ion?

  -

  
• What is the charge of a manganate ion?

  2-

  
• What is the charge of a phosphate ion?

  3-

  
• What is the charge of a hydrogen carbonate ion?

  -

  
• What is the charge of a hydroxide ion?

  -

  
• What is the charge of an ammonium ion?

  +

  
• What is the empirical formula?

  The simplest whole number ratio of elements/ions in a compound.
• Ionic compounds with stronger ionic bonding .....

  Have higher melting and higher boiling points because there is a strong electrostatic attraction between oppositely charged ions.
• The greater the charge of the ions in an ionic compound the stronger the ionic bonding. The larger the ions in an ionic compound the weaker the ionic bonding and down a group, the size of ions increases.