Chemistry Ions

Section 6 Definitions Valence Electrons Lewis (Electron) Dot Structures Octet Rule Cation Anion Halide Ion

How High Are You? Elements in a group behave similarly because of VALENCE ELECTRONS Electrons in the highest occupied energy level of an element’s atoms For representatives, the GROUP # indicates the # of v. e. Example: Group 2A has two v.e.’s, all in the s sublevel Group 4A? 7A?

For group A elements, LEWIS DOT STRUCTURES show v.e.’s as dots

Write the symbol of the element Count the number of valence electrons When drawing Lewis Dot Structures… Write the symbol of the element Count the number of valence electrons Put a dot for each valence electron the element has around the symbol in the north, south, east, and west position There must be one dot in each position before you can start pairing them For now, there can only be a maximum of 2 at each position for a max of 8 total

Draw the Lewis Dot Structures for the following elements Sodium Magnesium Aluminum Sulfur Argon Bromine

Great Eight Total # of e- that can be in s and p sublevels? 8 OCTET RULE: When forming compounds, atoms tend to achieve noble gas e- configuration General noble gas e- configuration is ns2np6 Other elements can’t be the noble gases, but can be like them Have a pseudo noble gas configuration (p.n.g.c) Elements will lose or gain electrons to achieve p.n.g.c Elements will take shortest path to NEAREST noble gas

Meow Cations form when metals lose one or more electrons to attain pseudo noble gas configuration Losing electrons, or negative particles, makes the element more positive The name of the cation that forms is simply the element’s name followed by “ion” Ex. Na loses one electron  Na+ or the sodium ion (that’s the name) Ex. Ca loses two electrons  Ca2+ or the calcium ion

Most metals in the representative element group are easy to predict Transition metals not as predictable Iron (Fe) can lose two or three electrons, forming Fe2+ or Fe3+ There are exceptions to the octet rule but they won’t be covered

Gimme Gimme Nonmetals tend to gain electrons to attain pseudo noble gas configuration Gaining electrons makes the element more negative Name of anion typically ends in –ide Example: Chlorine gains one electron  Cl- or the chloride ion Br - is bromide ion, O2- is oxide ion Anions from group 7A are called HALIDE IONS

Oxidation/Reduction Elements found naturally have already given or taken electrons to become noble-like Elements can be extracted and “saturated” with electrons to make them neutral again Ca = 20 p+ and 20 e- will be neutral These “pure” elements will then try to become like the nobles again An element that has lost an electron has become “oxidized” An element that has GAINED an electron has become “reduced”

Section 6 Assignment PG 193 Questions 3-7, 9-10 Also, tell me how many electrons they lose/gain, the symbol and name for the ion the following elements will form Magnesium Aluminum Phosphorus Sulfur Rubidium Nitrogen Lithium Fluorine Potassium