Reflecting on bonding Brainstorm everything you already know about bonding. You have one minute

Lesson 1 Ionic Bonding

Lesson 1: Ionic Bonding Objectives: Reflect on prior knowledge of bonding Refresh knowledge and understanding of ionic bonding

Homework Research and make notes on metallic bonding. Including: Description of the nature of the metallic bond Factors affecting the strength of metallic bonds Explanation of the malleability of metals Explanation of the electrical conductivity of metals Factors affecting the conductivity of metals

Overview

Recapping ionic bonding An ionic bond is: The electrostatic attraction between two oppositely charged ions sodium fluoride lithium oxide Ionic bonds typically form between a metal and a non-metal Ionically bonded compounds are often referred to as salts Na+ F- Li+ O2-

Formation of simple ions Positive ions (cations) Positive ions are formed when metals lose their outer shell electrons Group 1: Li  Li+ + e- Group 2: Ca  Ca2+ + 2e- Group 3: Al  Al3+ + 3e- Transition metals – form multiple different ions Fe  Fe2+ + 2e- Fe  Fe3+ + 3e- Negative ions (anions) Negative ions are formed when non-metals gain enough electrons to complete their outer shells Group 5: N + 3e-  N3- Group 6: O + 2e-  O2- Group 7: F + e-  F-

Polyatomic ions Many ions are made of multiple atoms with an overall negative charge The negative ones are mostly acids that have lost their hydrogen(s) You need to know about: Sulphate, SO42- Phosphate, PO43- Nitrate, NO3- Carbonate, CO32- Hydrogen carbonate, HCO3- Ethanoate (acetate), CH3CO2- Hydroxide, OH- Ammonium, NH4+

The formula of ionic compounds Ionic compounds are always neutral, so the charges must balance Example 1: calcium reacting with fluorine: Calcium forms Ca2+, fluorine forms F- The formula is CaF2 so two F- charges cancel the one Ca2+ Example 2: iron (II) reacting with phosphate Iron (II) is the Fe2+ ion, phosphate is PO43- The formula is Fe3(PO4)2 The 6+ charges from iron (2+ x 3) balance the 6- charges (3- x 2) from phosphate Look for the lowest common multiple Ionic compounds do not form molecules so these are always empirical formulae

The names of ionic compounds The cation gives the first part of the name Normally a metal except in the case of ammonium (NH4+) In the case of transition metals, Roman numerals tell you the charge on the metal ion The anion gives the second part of the name Simple ions: ‘-ide’…e.g. chloride, fluoride, nitride etc Complex ions: just their name: sulphate, phosphate etc Note: the ‘-ate’ ending usually refers to polyatomic ions containing oxygen, which provides the negativity…more on this in the redox unit Examples: CaF2: calcium fluoride Fe3(PO4)2: iron (II) phosphate

Your turn Deduce the formulae and names of the ionic compounds formed between: Lithium and fluorine Magnesium and iodine Aluminium and oxygen Iron (II) and sulphur Calcium and nitrogen Sodium and sulphate ions Chloride and ammonium ions Iron (III) and sulphate ions Iron (II) and nitrate ions Potassium and carbonate ions Work through the simulation here: http://www.learner.org/interactives/periodic/groups_interactive.html

Key Points Ionic bonds are the attraction between two oppositely charged ions Ionic bonds form between metals and non metals Metals lose their outer shell Non-metals complete their outer shell The number of each ion in the formula is determined by the lowest common multiple of their charges