Chap 5 Flashcards
Valence electrons
Electrons in the highest occupied energy level, involves only the s & p sublevels (B/c of the sublevel filling sequence). Can hold up to eight electron
For main group elements the column or group number is
also the number of valence electrons
Lewis dot symbols
Represent electrons as dots around atomic symbol
Octet rule
What group fulfills the octet rule?
Other atoms fulfill the octet rule by:
An atom is stabilized by having its valence energy level filled.
Noble gasses
gaining or loosing electrons (ions) or by sharing electrons
Ions
Atom or groups of atoms that have an overall charge
Cations, what are they how do they come about
Positively charged Ions
Atoms form cations by loosing electrons
Main group metals fulfill the octet rule by forming cations
Generally, what are the charges of the ions of the alkali metals and alkaline earth metals?
+1 and +2, respectively
Naming cations, and transition metal cations that have more than one charge.
Metal cations have the same name as the neutral metals
Transition metals with different charges, their charges are listed as roman numerals immediately after the atom’s name ( Fe^2+ = Iron(II))
Naming Anions
When atom gains electrons, the resulting anion is named by changing the end of the atom name to -ide
(Sulfur-Sulfide)
Polyatomic ions
Groups of atoms with a charge
What are oxyanions
Naming oxyanions
Oxyanions- polyatomic ions that involve oxygen.
Usually named as: element root + -ate
(CO^2- 3 -Carbonate)
for those with more than one oxyanion:
the ones with fewer oxygens end in -ite
the ones with more oxygens ends in -ate
-the one with fewer oxygens than the one with -ite has a subfix Hypo-
-the one with more oxygens than the one with -ate has subfix per-
Ionic bond
An attraction between oppositely charged atoms
Ionic compound, composed of
Composed of charged ions
Metal cations and nonmmetal anions form ionic compounds
Positive charges must equal negative . Total charge =0
Empirical formula:
for ionic compounds (?)
The smallest whole number ratio of atoms
subscripts written after each atom indicate the number of that atom present
Cation then anion is written
no subscript written, understood to be one
“-ate is great and -ite is light”
Mote oxygen atoms: -ate
fewer oxygen atoms: -ite
Formula unit
Empirical formula gives the smallest number of ions necessary to form a compound. This # of ions is the formula unit
Naming ionic compounds
Cation- anion
polyatomic too
positives and negatives must equal each other to be a neutral solid so there is no need to specify amounts or charges
Naming Ionic compounds w/ transition metals
cation - anion
The balance in the cation needed to balance the charge of the anion is written after the cation name in parentheses.
(CUCl2 - Copper (II) chloride)
Covalent bond
Electrons are shared between two bonds to form molecules
By sharing electrons, each atom fills its valence level
Atoms sometimes share two or more electrons
Covalent Compunds
form when elements combine through covalent bonds forming discreet molecules
Molecular formula
Gives the number of atoms in the molecule
Often have complex structures
(Empirical: NH2 Molecular: N2H4)
Naming binary covalent compounds (containing only two atoms)
From the periodic table, the atom on the left is named first and the whole name is used
The one to the right is second and named as an anion (subfix -ide)
Prefixes are used in front of each element (except for mono on the first element) to indicate how many atoms there are
Ionic vs Covalent bonds
Covalent:
Share electrons and are between nonmetal atoms, usually form molecules, use molecular formula.
Ionic:
Are between oppositely charged atoms, don’t form molecules, described by formula unit or empirical formula
composed of a metal and a nonmetal
Aqueous solution
A homogeneous mixture in which the main component is water
Soluble
able to dissolve (in water)
electrolyte soluiton
ionic compounds dissolved in water
dissociation
Ions are pulled apart in an aqueous solution
Acids
Covalent compounds that produce H+ ions in an aqueous solution
an exception to the fact that covalent compounds generally do not form ions in water. and are not electrolytes.
Writing formulas for acids
Write hydrogen first, as if it were a cation
Binary acids, and how are they named
Consist of H+ and a single nonmetal element.
By the prefix hydro, the root of the element, and the subfix -ic acid
Oxyacids and naming them
(dissociate to form) Form H+ and oxyanions
1) -ate —> -ic acid
2) -ite —> -ous acid
