structure and bonding

• What are the three types of bonding between atoms?

  Ionic, covalent and metallic
• What is an ionic bond?

  An attraction between oppositely charged ions
• What is a covalent bond?

  A bond formed when electrons are shared between atoms
• What is a metallic bond?

  A bond formed when metal atoms share delocalised electrons
• When does ionic bonding occur?

  When a metal reacts with a non-metal
• When does covalent bonding occur?

  When a non-metal reacts with a non-metal
• When does metallic bonding occur?

  In metals and alloys
• Why do atoms of elements react?

  In order to get a full outer shell of electrons
• Why do Group 0 (noble gas) elements NOT react?

  They already have a full outer shell
• How does an ionic bond form?

  The metal atoms transfers electrons to the non-metal atom
• When Group 1 metals react, what charge do their ions have?

  1+
• When Group 2 metals react, what charge do their ions have?

  2+
• When Group 3 metals react, what charge do their ions have?

  3+
• When Group 7 non-metals react, what charge do their ions have?

  1-
• When Group 6 non-metals react, what charge do their ions have?

  2-
• What structure does an ionic compound have?

  Giant structure of ions
• What holds an ionic compound together?


  The strong electrostatic forces of attraction acting between positive and negative ions
• What are the limitations of using a dot and cross diagram to represent a giant ionic structure?

  A dot and cross diagram does not show how the atoms are arranged in space.
• What are the limitations of using a two-dimensional model to represent a giant ionic structure?


  A two-dimensional space-filling model does not show how the next layer of ions is arranged
• What are the limitations of using a three-dimensional ball and stick model to represent a giant ionic structure?


  Using sticks for bonds is misleading because the forces of attraction between ions actually act in all directions
• What are the limitations of using a three-dimensional model to represent a giant ionic structure?

  A three-dimensional model is misleading because it shows lots of free space between the ions, which there isn't
• How do atoms form covalent bonds?

  By sharing pairs of electrons
• Describe the strength of a covalent bond

  Strong
• What do most covalently bonded substances consist of?

  Small molecules
• What is the chemical formula of hydrogen?

  H2
• What is the chemical formula of oxygen?

  O2
• What is the chemical formula of nitrogen?


  N2
• What is the chemical formula of hydrogen chloride?

  HCl
• What is the chemical formula of water?

  H2O
• What is the chemical formula of methane?

  CH4
• What is the chemical formula of ammonia?

  NH3
• How do you know from the formula of a substance that it is covalently bonded?

  The elements in the molecule are all non-metal elements
• Give an example of a covalently bonded substance that has very large molecules

  Polymers
• Give two examples of covalently bonded substances that has giant covalent structures

  Diamond and silicon dioxide
• What are the limitations of using a dot and cross diagram to represent molecules or giant structures?

  A dot and cross diagram does not show the relative sizes of the atoms, or how they are arranged in space
• What are the limitations of using a three-dimensional ball and stick model to represent molecules or giant structures?

  A three-dimensional ball and stick model does not show the true shape of the molecule
• What is the structure of a metal?

  A metal is a giant structure of atoms arranged in a regular pattern
• What happens to electrons in a giant metal structure?

  The outer electrons are delocalised and so are free to move through the whole structure
• Why are metallic bonds strong?

  The sharing of delocalised electrons give rise to strong bonds
• What are the three states of matter?

  Solid, liquid, gas