Chapter 3 Flashcards
1
Q
Ionic Compounds
A
- bonding occurs as result of electrostatic attraction between oppositely charged particles
- the sum of the ionic charges in the formula is always zero
- lowest ratio of the ions in an ionic compound is called formula unit
- arranged in 3D ion network called a crystal lattice (each ion surrounded by oppositely charged nearest neighbors and held tightly in its position at room temperature)
- stabilized when 6 cations/anions surround 1 anion/cation
- ionic bonds account for high melting points and boiling points
- often between a METAL and NONMETAL
examples: NaCl, NaHCO3 (sodium bicarbonate/baking soda), CaCO3
2
Q
Covalent Compounds
A
- bonding occurs as a result of sharing a pair of electrons between two atoms
- more predominant than ionic compounds
- also known as MOLECULAR COMPOUNDS
- made of NONMETALS
examples: H2O, C12H22O11 (sucrose/table sugar), C3H8 (propane gas)
3
Q
Cations
A
- when neutral atom loses one or more electrons to become positively charged because has fewer negative electrons than it has positive protons in nucleus
- size SMALLER than neutral atom due to increased nuclear attraction on orbiting electrons
- METAL ATOM ionizes to form a cation
example: Li atom -> Li+ cation + e-
4
Q
Anion
A
- when neutral atom gains one or more electrons to become negatively charged because it now has one or more negative electrons than positive protons
- size LARGER than neutral atom due to increased electrostatic repulsion of like-charge electrons in the presence of a net negative charge on the ion
- NONMETAL ATOM ionizes to form an anion
example: F atom + e- -> F- anion
5
Q
Nomenclature for metal ions with various charges
A
- roman numeral indicates charge on the ion; placed in parentheses after metal name
- can use common names as well ( -ous = ion of lower charge and -ic = ion of higher charge)
example:
Fe 2+ = iron (II) ion or ferrous ion
Fe 3+ = iron (III) ion or ferric ion
Hg2 2+ = mercury (I) ion or mercurous ion
Hg 2+ = mercury (II) ion or mercuric ion
6
Q
Nomenclature tips for Polyatomic Anions
A
- use suffix -ate when greater number of Oxygen atoms
- use suffix -ite when lower number of Oxygen atoms
- use prefix per- and suffix -ate when with four Oxygen atoms
- use prefix hypo- and suffix -ite when with one Oxygen atom
7
Q
Two transition elements with one charge
A
Ag+
Zn 2+
8
Q
Nomenclature for binary covalent/molecular compounds
A
- between two different nonmetal elements
- ) name 1st nonmetal element in formula, using a prefix if needed to indicate the number of atoms. The prefix mono- is usually omitted in the first word.
- ) Name the 2nd nonmetal element in the formula, using a prefix if needed and the suffix -ide at the end.
- When prefix used to name a compound that results in 2 vowels being adjacent to one another, the first vowel in the prefix is usually omitted. The exception is the vowel i, which is normally not dropped.
1 = mono- 2 = di- 3 = tri- 4 = tetra- 5 = penta- 6 = hexa- 7 = hepta- 8 = octa- 9 = nona- 10 = deca-
9
Q
Diatomic Elements (7)
A
Hydrogen, Oxygen, Nitrogen, Chlorine, Iodine, Bromine, Fluorine
10
Q
Nomenclature for Binary Acids
A
- contains 2 different elements
- ) prefix “hydro-“
- ) stem name of anion
- ) suffix “-ic”
- ) word “acid” used as the second word in the name
* acids are in (aq) form/dissolved in water*
11
Q
Nomenclature for Oxyacids
A
- acids that contains of at least one H+ ion and an oxyanion/oxoanion (polyatomic ion that contains one or more oxygen atoms and a nonmetal atom)
- ) no prefix used
- ) use stem name of polyatomic ion
- ) if name of the polyatomic ion ends in -ate, then change it to -ic
- ) if name of polyatomic ion ends in -ite, then change it to -ous
- ) add the word “acid” at the end
12
Q
Nomenclature for hydrated compounds
A
- solid crystals that include H2O molecules as part of the crystal structure
- to determine the amount of H2O molecules associated with each formula unit of the hydrated ionic compound, must be experimentally determined
- ) ionic compound (without the waters of hydration) is named first using the rule for naming ionic compounds
- ) Greek prefixes are attached to the word “hydrate” to indicate the number of water molecules per formula unit for the compound
- ) When the chemical formula for a hydrated ionic compound is written, the formula for the ionic compound is separated from the waters of hydration by a “dot”
13
Q
Mass Percent Composition
A
- %A = [(parts of A in mixture) ÷ (total parts in the mixture)] × 100
- mass % of X = [(mass of X in 1 mol of compound) ÷ (mass of 1 mol of compound)] × 100
- can be used as conversion factor (SEE LECTURE, HW, AND TEST FOR EXAMPLES)
14
Q
Empirical Formulas of Compounds
A
- simplest ratio of atoms of the elements in the compound
- ) Find the masses of different elements in a sample of the compound.
- ) Convert the masses into moles of atoms of the different elements.
- ) Determine the ratio of moles of atoms.
- ) Express the moles of atoms as the smallest possible ratio of integers.
- ) Write the empirical formula, using the number for each atom in the integer as the subscript in the formula.
REFER TO LECTURE, HW, AND TEST FOR EXAMPLES
15
Q
Molecular Formula of a Compound
A
- ) Determine the molecular formula of the compound.
- ) Calculate the molar mass of the empirical formula.
- ) Determine the molar mass of the compound (usually given).
- ) Divide the molar mass of the compound by the molar mass of the empirical formula to obtain a multiplication factor n.
- ) Multiply the empirical formula by a factor n to obtain the molecular formula
REFER TO LECTURE, HW, AND TEST FOR EXAMPLES
