Topic 2 – Ionic Compounds and Analysis 25/04/2017 Starter: What is an element? What is a compound? What is a mixture? EXT: What do you think an ion is?

Sodium chloride (salt) Compounds 25/04/2017 Sodium chloride (salt) Methane Compounds are formed when two or more elements are chemically combined. Some examples: Glucose 2.1 Be able to demonstrate an understanding that atoms of different elements can combine to form compounds by the formation of new chemical bonds How are these compounds formed? Let’s consider two ways – “ionic” and “covalent” bonding. We are going to focus on ionic

Naming compounds 25/04/2017 Rule 1 – When two elements join and one is a halogen, oxygen or sulphur the name ends with ____ide e.g. Magnesium + oxygen magnesium oxide Sodium + chlorine Magnesium + fluorine Lithium + iodine Chlorine + copper Oxygen + iron KBr LiCl CaO MgS KF 2.5 Be able to demonstrate an understanding of the use of the endings –ide and –ate in the names of compounds

e.g. Copper + sulphur + oxygen Copper sulphate Naming compounds 25/04/2017 Rule 2 – When three or more elements combine and one of them is oxygen the ending is _____ate e.g. Copper + sulphur + oxygen Copper sulphate Calcium + carbon + oxygen Potassium + carbon + oxygen Calcium + sulphur + oxygen Magnesium + chlorine + oxygen Calcium + oxygen + nitrogen AgNO3 H2SO4 K2CO3

Introduction to Bonding 25/04/2017 Cl Hi. My name’s Johnny Chlorine. I’m in Group 7, so I have 7 electrons in my outer shell Cl I’d quite like to have a full outer shell. To do this I need to GAIN an electron. Who can help me?

Here comes a friend, Sophie Sodium Ionic Bonding 25/04/2017 Cl Here comes a friend, Sophie Sodium Na Hey Johnny. I’m in Group 1 so I have one electron in my outer shell. I don’t like only having one electron there so I’m quite happy to get rid of it. Do you want it? Okay - + Cl Na Now we’ve both got full outer shells and we’ve both gained a charge which attracts us together. We’ve formed an IONIC bond.

Ions 25/04/2017 An ion is formed when an atom gains or loses electrons and becomes charged: + - The electron is negatively charged The proton is positively charged + + If we “take away” the electron we’re left with just a positive charge: 2.2 Be able to describe how ionic bonds are formed by the transfer of electrons to produce cations and anions 2.3 Be able to describe an ion as an atom or group of atoms with a positive or negative charge This is called an ion (in this case, a positive hydrogen ion, also called a cation).

Words – full, transfers, positively, negatively, metals, anion, stable Ionic bonding 25/04/2017 This is where a metal bonds with a non-metal (usually). Instead of sharing the electrons one of the atoms “_____” one or more electrons to the other. For example, consider sodium and chlorine: Na Cl Sodium has 1 electron on its outer shell and chlorine has 7, so if sodium gives its electron to chlorine they both have a ___ outer shell and are ______. Na + A _______ charged sodium ion (cation) A _________ charged chloride ion (______) Cl - 2.4 Be able to describe the formation of sodium ions, Na+, and chloride ions, Cl-, and hence the formation of ions in other ionic compounds from their atoms, limited to compounds of elements in groups 1, 2, 6 and 7 Group 1 _______ will always form ions with a charge of +1 when they react with group 7 elements. The group 7 element will always form a negative ion with charge -1. Words – full, transfers, positively, negatively, metals, anion, stable

Naming Ionic compounds worksheet 25/04/2017 Naming Ionic compounds worksheet Rule 1 – When two elements join and one is a halogen, oxygen or sulphur the name ends with ____ide e.g. Magnesium + oxygen magnesium oxide Rule 2 – When three or more elements combine and one of them is oxygen the ending is _____ate e.g. Copper + sulphur + oxygen Copper sulphate

The Periodic Table 25/04/2017 25/04/2017 Looking at their position in the Periodic Table and understanding their electron structure, we can predict the charge of different ions. For example, group 1 elements all want to lose one electron so they will all form cations with a charge of +1 What type of ion (and its charge) will elements from groups 2, 6 and 7 form? H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Fe Ni Cu Zn Br Kr Ag I Xe Pt Au Hg

Some examples of ionic bonds 25/04/2017 Cl - Magnesium chloride: Cl Mg 2+ Mg + Cl - Cl MgCl2 Calcium oxide: This is how you would draw ionic compounds O Ca + 2+ 2- CaO

Balancing ions Some common ions: 25/04/2017 25/04/2017 Some common ions: Sodium – Na+ Potassium – K+ Magnesium – Mg2+ Ammonium – NH4+ Chloride – Cl- Bromide – Br- Oxide – O2- Sulphate – SO42- Determine the formula of these compounds: Sodium chloride Magnesium oxide Magnesium chloride Ammonium chloride Sodium sulphate Sodium oxide Answers: NaCl MgO MgCl2 NH4Cl Na2SO4 NaO 2.6 Deduce the formulae of ionic compounds (including oxides, hydroxides, halides, nitrates, carbonates and sulfates) given the formulae of the constituent ions EXT: Draw them!

Drawing ions and ionic compounds worksheet

Structure of ionic compounds The ions in an ionic compound are arranged in a very regular way. This structure is known as a lattice structure. Why do you think they arrange themselves like this?

Giant Ionic Structures 25/04/2017 Cl- Na+ When many positive and negative ions are joined they form a “giant ionic lattice” where each ion is held to the other by strong electrostatic forces of attraction (ionic bonds). TASK: Put together a ‘Chemistry for dummies’ guide on ions, ionic bonding and ionic compounds 2.7 Be able to describe the structure of ionic compounds as a lattice structure (HT only): a) consisting of a regular arrangement of ions b) held together by strong electrostatic forces (ionic bonds) between oppositely-charged ions

Giant Ionic Structures 25/04/2017 Cl- Na+ When many positive and negative ions are joined they form a “giant ionic lattice” where each ion is held to the other by strong electrostatic forces of attraction (ionic bonds). Reference to next lesson :If these ions are strongly held together what affect would this have on the substance’s: Melting point? Boiling point? State (solid, liquid or gas) at room temperature? 2.7 Be able to describe the structure of ionic compounds as a lattice structure (HT only): a) consisting of a regular arrangement of ions b) held together by strong electrostatic forces (ionic bonds) between oppositely-charged ions