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Ionic Bonding Naming and formula writing. Mrs. Kay Chemistry 11 Read pages 158-168. Atoms of different elements have different numbers of electrons Each shell is filled up before electrons move to the next shell found further away from the nucleus
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Ionic BondingNaming and formula writing Mrs. Kay Chemistry 11 Read pages 158-168
Atoms of different elements have different numbers of electrons • Each shell is filled up before electrons move to the next shell found further away from the nucleus • Ex: Sodium has 2 e- on the 1st energy level, 8 e- on the 2nd energy level, and 1 e- on the 3rd energy level. Sodium has 1 valence electron
Valence electrons • Period number indicates the number of electron shells • Group number indicates the number of valence electrons (look at the second digit of the group number)
Trends: • Elements of the same group have similar chemical properties because they have the same number of electrons in their outer shell or valence shell • Group 1 metals reacting with water
Reasons for reactions • Group 18, the noble gases are the most stable of elements because their valence shell is full with electrons • Less energy required to support the atom • Other atoms react in attempt to achieve nobel gas configuration, same number of valence electrons as a noble gas.
Lewis Dot structures • Visual representation of an element and only its valence electrons • sodium, Na has 1 valence so it has 1 dot representing that electron. (group 1) • Chlorine, Cl has 7 electrons. (group 17) • Electrons get placed up along 4 sides of the element before they double up!
Ionic Bonding • attraction between oppositely charged ions formed when metallic ions (+) transfer electron(s) to nonmetallic ions (-) • Difference of electronegativity greater than 1.7 • Ex: NaCl
Not always 1:1 ratio, sometimes need to use subscript to show the number of atoms Ex: CaCl2 The 2 is a subscript, it shows that 2 atoms of chlorine bond with one atom of calcium. Zero Sum Rule: the charges need to add up to zero
Simple Ionic Compounds • KBr • Name the metal first • Potassium • Name the non-metal next, end it with –ide • Bromine becomes bromide • Put together: Potassium bromide
Practice • Na2O Name the metal: Sodium Oxide Name the non-metal: • Put them together to get: Sodium Oxide. • It takes two Na+ to combine with one O2- to observe the Zero Sum Rule!
If you’re given the name, can you write the formula? • Strontium nitride • Strontium is Sr2+ • Nitride is N3- • We must combine them to be equal to zero • Need 3 Sr2+ to combine with 2 N3- • Answer is Sr3N2
Multivalent Ionic bonding • Whenever the periodic table of ions has a split cell, we must choose or indicate which charge we are refering to in the chemical equation. • Look at Iron • There is an option of Fe2+ and Fe3+ • FeO would be called Iron (II) oxide • It takes Fe2+ to balance out charges with O2- • We indicate the optional charge with roman numerals; 2= II, 3=III, 4=IV and so on
Practice naming • FeCl2 • MnO • Fe2O3 • TiO2 • Iron (II) chloride • Manganese (II) oxide • Iron (III) oxide • Titanium (IV) oxide
Polyatomic ions • Ions that are made of multiple atoms covalently bonded together. • We treat them like a unit or package • When we need more than one, must be put in brackets!! • Example: sulphate, SO42- • Aluminum sulphate = Al2(SO4)3 • Because is Al3+ and SO42- must combine to Zero
Practice • NaOH • K3PO4 • CsMnO4 • Ca(HCO3)2 • Cu(NO3)2 • Sodium hydroxide • Potassium phosphate • Cesium permanganate • Calcium hydrogen carbonate • Copper (II) nitrate
Homework: • Don’t forget to read over the textbook pages for furhter understanding • Work on handouts to continue practice with naming and proper formula writing (IUPAC = international naming method, what we learned)
Test what you know here:http://science.widener.edu/svb/tutorial/namingcsn7.html