2 atoms and ions


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2 atoms and ions

  1. 1. Atoms and IonsSNC 2D1
  2. 2. Is drinking too much water badfor you?? Drinking too much water cancause hyponatremia◦ Symptoms: disorientation andloss of balance Excess water can dilute theconcentration of sodium in theblood to dangerously lowlevels (with risk of death ifuntreated)
  3. 3. What?Sodium in the blood??
  4. 4. No! of course not.. We are referring to sodium ions Many ions are necessary for ourhealthExample:◦ Calcium, phosphorus  components ofbone◦ Iron  help carry oxygen around body inblood
  5. 5. Atoms vs. Ions Atoms are electrically NEUTRALparticles with equal numbers of e- andp+ An ion is an atom that has becomeCHARGED by either gaining orlosing electrons in its valence shell
  6. 6. Sodium Atom vs. Sodium Ion Sodium atoms LOSE one e-when they react with otheratoms Then, each sodium ioncontains 11 p+ and only 10 e- Result: sodium ions have anionic charge of +1 (a.k.a. Na1+or Na+)Na containsONE electron init’s outer orbit.Remember…STABLE orbitscontain 8electrons!! Sowhat does thismean?
  7. 7. Fluorine Atom vs. Fluoride Ion Fluorine atoms GAIN oneelectrons when they react withother atoms Therefore, each fluoride ioncontains 9 p+ and 10 e- Result: fluoride ions have anionic charge of -1 (a.k.a. F1- or F-)F-9 contains 7electrons in itsouter orbitRemember…STABLEorbits contain8 electrons!! Sowhat does thismean?
  8. 8. Ions vs. Noble Gases Ions are STABLE Noble Gases are alsoSTABLE Because they havefilled valence shells… Which noble gas hasthe same # of e- asNa+? Which noble gas hasthe same # of e- as F-? We say Na+ and F- isisoelectronic to Ne
  9. 9. DID YOU KNOW? Fluoride ions help make tooth enamel strong Fluoride is found in our tap water For decades, Canadians have been gettingfewer dental cavities
  10. 10. Try This!!1)Draw the B-R diagram for anAluminum atom2)Draw the B-R diagram for anAluminum ion3)Write the new symbol for theAluminum ion4)What is the Aluminum ionisoelectronic with? (i.e. whatelement has the same # ofelectrons as the aluminum ion?
  11. 11. Aluminum ion Al:13p+, 13n0, 13e- Draw the Bohr-Rutherforddiagram: 3 valence e- How to reachstability? Gain 5 or lose 3 e-?What is Al3+ isoelectronic with?Neon!
  12. 12. Try This!!1)Draw the B-R diagramfor a Sulfur atom2)Draw the B-R diagramfor a Sulfide ion3)Write the new symbolfor the Sulfide ion4)What is the sulfide ionisoelectronic with?(i.e. what element hasthe same # ofelectrons as the
  13. 13. Sulfide ionS: 16p+, 16n0, 16e- Draw the Bohr-Rutherford diagram: 6 valence e- How to reachstability? Gain 2 or lose 6 e-?What is S2- isoelectronic with?Argon!
  14. 14. Hydrogen Unusual element Can form +ve and –ve ions Achieves stability by gaining one e- tofill its orbit (H-) or loses its only e- (H+)
  15. 15. Naming Ions Cations: positive charges Same name as the element and addthe word “ion” E.g. Sodium  Sodium ion Anions: negative charges Add “-ide” to the stem of the name E.g. Oxygen  oxide ion E.g. Phosphorus  phosphide ions