Ionic Bonding Naming and formula writing
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
Ionic Bonding Naming and formula writing
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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