BONDING

• What type of elements are sodium and chlorine?

  Sodium is a metal and chlorine is a non-metal
• What do the dots and crosses represent in the diagrams?

  Electrons
• What is the electron configuration of sodium and chlorine?

  The number of protons equals the number of electrons, making both atoms neutral
• Why do many atoms react?

  To achieve the electron configuration of a noble gas
• How does sodium achieve the electron configuration of neon?

  By losing one electron
• How does chlorine achieve the electron configuration of argon?

  By gaining one electron
• What happens to the sodium atom when it loses an electron?

  It forms a sodium ion with a charge of positive one
• What happens to the chlorine atom when it gains an electron?

  It forms a chloride ion with a charge of negative one
• What do both ions achieve after the transfer of electrons?

  They have the same electron configuration as a noble gas
• What do the square brackets in the ion diagrams indicate?

  The charge is spread over the whole ion
• What attracts the positive and negative ions to each other?

  Electrostatic forces of attraction
• What should you complete for the ions formed from magnesium and oxygen?

  The dot and cross diagrams for the ions
• How many electrons from the magnesium atom are transferred to the oxygen atom?

  Two electrons
• What is the electron configuration of the ions formed from magnesium and oxygen?

  Both ions have the same electron configuration as the noble gas neon
• What are the steps in the formation of ionic compounds?

  1. Metal loses electrons to achieve noble gas configuration.
  2. Non-metal gains electrons to achieve noble gas configuration.
  3. Ions are formed with opposite charges.
  4. Ions attract each other due to electrostatic forces.
• What are the physical properties of ionic compounds related to their structure?

  • High melting and boiling points
  • Soluble in water
  • Conduct electricity when dissolved or molten
  • Form a giant ionic lattice structure
• What is the structure formed by ionic compounds called?

  Giant ionic lattice
• How do ions in a giant ionic lattice interact with each other?

  They are attracted to every other oppositely charged ion
• What are the forces that hold the ions in a giant ionic lattice together?

  Electrostatic forces of attraction
• What are the common physical properties of ionic compounds explained by the giant ionic lattice?

  • Very high melting and boiling points
  • Solubility in polar solvents
  • Do not conduct electricity when solid
  • Conduct electricity when melted or dissolved in water
• What is the melting point of sodium chloride?

  801 degrees Celsius
• What is the melting point of magnesium oxide?

  2852 degrees Celsius
• Why do ionic compounds have high melting and boiling points?

  Because it takes a great deal of energy to overcome the strong electrostatic forces of attraction
• Why are ionic compounds soluble in polar solvents like water?

  Water molecules surround the ions and can overcome the electrostatic attraction between them
• How does the charge of ions affect the solubility of ionic compounds in water?

  Higher charges on ions often decrease solubility due to stronger electrostatic forces
• Why do ionic compounds not conduct electricity when solid?

  Because the ions are locked in place and cannot move
• Under what conditions can ionic compounds conduct electricity?

  When they are melted or dissolved in water
• What happens to ionic compounds when they are dissolved in water?

  • Water molecules surround the ions
  • Electrostatic attraction between ions is overcome
  • Ions become free to move
• A molecule can be defined as an electrically neutral group of two or more atoms held together by chemical bonds.
• Molecules are formed when atoms share electrons to form stable electron configurations.
• The bonding between the two atoms is called covalent bond
• The simplest covalently bonded molecule is hydrogen (H2).
• What is meant by a covalent bond?

  A covalent bond is formed when two non-metal atoms share electrons.
• What are the steps to draw dot and cross diagrams for covalent molecules?

  • Identify the atoms involved.
  • Determine the number of valence electrons.
  • Show the sharing of electrons between atoms.
  • Represent shared pairs with dots and crosses.
• What happens during ionic bonding?

  Ionic bonding involves the transfer of electrons from a metal atom to a non-metal atom.
• What occurs when a non-metal reacts with another non-metal?

  Covalent bonding takes place when a non-metal reacts with another non-metal.
• How many electrons do hydrogen atoms have in their outer shell?

  Hydrogen atoms have one electron in their 1s orbital of their outer shell.
• What happens when two hydrogen atoms react?

  Their 1s orbitals overlap and the electrons are shared, forming a covalent bond.
• What molecule is formed when two hydrogen atoms bond?

  The hydrogen molecule, H₂, is formed.
• What is the attraction in a covalent bond?

  The shared pair of electrons is attracted to the two nuclei of the atoms forming the bond.