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Ionic Bonding Naming and formula writing

Ionic Bonding Naming and formula writing. Mrs. Kay & Ms. Cleary Chemistry 11 Read pages 158-168. Recall. 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 Bonding Naming and formula writing

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  1. Ionic BondingNaming and formula writing Mrs. Kay & Ms. Cleary Chemistry 11 Read pages 158-168

  2. Recall • 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

  3. 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)

  4. 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

  5. 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.

  6. 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!

  7. 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

  8. 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

  9. Naming Ionic Compounds

  10. Simple or Binary Ionic Compounds (Formula to Name) • KBr • Name the (cation) metal first • Potassium • Name the root of the (anion) non-metal, change the (suffix) end to –ide • Bromine becomes bromide • Put together: Potassium bromide

  11. 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!

  12. Simple or Binary Ionic Compounds (Name to Formula) To write the formula from a name first you must look at the charges. Remember ionic compounds are made up of cations and anions (oppositly charged ions) but together the compound has no charge- the charges balance each other out.

  13. “Cross-over Method” • This is a method used to make sure your compound is balanced. • Write the formulas of the ions beside each other, then cross the number of the charge of the cation so that it becomes the subscript of the anion. Then cross over the number of the charge on the anion so that it becomes the subscript of the cation. Mg2+ Cl1- MgCl2

  14. Simple or Binary Ionic Compounds (Name to Formula) • 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

  15. Multivalent Ionic bonding • Whenever the periodic table of ions has a split cell, we must choose or indicate which charge we are referring to in the chemical equation. • Look at Iron, the charge on Fe is written as a roman numeral between the cation and the anion. • 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

  16. Practice naming • FeCl2 • MnO • Fe2O3 • TiO2 • Iron (II) chloride • Manganese (II) oxide • Iron (III) oxide • Titanium (IV) oxide

  17. 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

  18. Practice • NaOH • K3PO4 • CsMnO4 • Ca(HCO3)2 • Cu(NO3)2 • Sodium hydroxide • Potassium phosphate • Cesium permanganate • Calcium hydrogen carbonate • Copper (II) nitrate

  19. 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)

  20. Test what you know here:http://science.widener.edu/svb/tutorial/namingcsn7.html

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