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Specification covered

• 1.28 describe the
• formation of ions by the gain or loss of electrons
• 1.29 understand
• oxidation as the loss of electrons and reduction as the gain of electrons
• 1.30 recall the
• charges of common ions in this specification
• 1.31 deduce the
• charge of an ion from the electronic configuration of the atom from which the
• ion is formed
• 1.32 explain, using
• dot and cross diagrams, the formation of ionic compounds by electron transfer,
• limited to combinations of elements from Groups 1, 2, 3 and 5, 6, 7
• 1.33 understand
• ionic bonding as a strong electrostatic attraction between oppositely charged
• ions
• 1.34 understand that
• ionic compounds have high melting and boiling points because of strong
• electrostatic forces between oppositely charged ions
• 1.35 understand the
• relationship between ionic charge and the melting point and boiling point of an
• ionic compound
• 1.36 describe an
• ionic crystal as a giant three-dimensional lattice structure held together by
• the attraction between oppositely charged ions
• 1.37 draw a diagram
• to represent the positions of the ions in a crystal of sodium chloride.

Ions

• Ions are basically charged versions of atoms.
• If an atom loses an electron during a reaction, it will become positive. If an atom gains an electron, it will become negative. This is because electrons have a negative charge.
• Protons have a positive charge but they do not move around.
• https://www.youtube.com/watch?v=900dXBWgx3Y (Embed)

Oxidation and reduction

• https://www.youtube.com/watch?v=lQ6FBA1HM3s (Embed)
• OIL RIG
• oxidation is loss reduction is gain
• When something is oxidised, it loses electrons. When it is reduced, it gains electrons.

Chrages of ions

• Ions in this specification include:
• K +
• Na +
• Li +
• H +
• Mg 2+
• Ca 2+
• Al 3+
• Cl-
• Br-
• I-
• F-
• OH-
• SO4 2-
• CO3 2-
• NO 3-
• Charges of ions

Electronic config. and ions

• If an atom has four or less electrons in its outer shell, it will lose electrons in a reaction.
• If it has more than four electrons in its outer shell, it will gain electrons.
• REMEMBER: # of electrons in outer shell = group number

Videos: (ionic) bonding

• https://www.youtube.com/watch?v=zpaHPXVR8WU (Embed)
• https://www.youtube.com/watch?v=QXT4OVM4vXI (Embed)