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)
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
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
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?
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?
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
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
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?
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!
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
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!
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+)
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