Chapter 03A: Molecules, Compounds, and Chemical Equations Flashcards
Compound
Substance with 2+ elements CHEMICALLY combined in a DEFINITE proportion by mass
Can be decomposed into simpler substances
Chemical formula
An abbreviation for compounds
Contains symbols & ratio of atoms/elements
Molecular formula
Gives ACTUAL number of atoms of each element, in the smallest unit of substance
H2O
Empirical formula
Shows SIMPLEST (reduced) whole-number ratio of atoms in a substance
C6H12O6 –> CH2O
Structural formula
Uses lines to represent covalent bonds
Shows how atoms are connected or bonded to each other
Chemical bonds
Forces that hold atoms together in compounds
Ionic bond
Type of chemical bond
Attraction between oppositely charged ions
Occurs between metals (cations) and nonmetals (anions)
TRANSFER of 1+ electrons from metal to nonmetal
RESULT: Ionic compound
Covalent bond
Type of chemical bond
Occurs between 2+ nonmetals/metalloids
SHARING of electrons
RESULT: Molecule, molecular compound
Atomic elements
Exist in nature with single atoms as their basic units
Most elements fall into this category
Molecular elements
Exist normally in nature as molecules
Diatomic elements (7)
H - Hydrogen N - Nitrogen O - Oxygen F - Fluorine Cl - Chlorine Br - Bromine I - Iodine
Polyatomic elements (3)
P - Phosphorus (P4)
S - Sulfur (S8)
Se - Selenium (Se8)
Ionic compound
Cation + anion
Formula unit
Basic unit of ionic compound
The smallest, electrically neutral collection of ions
e.g. NaCl
Monatomic ion
1 atom
e.g. Na ion
Polyatomic ion
2+ atoms
e.g. nitrate
Nomenclature: ionic
Metal + nonmetal/anion
Cation (charge) + anion + ide
Nomenclature: molecular
Nonmetals/metalloids
Prefix (2+) + 1st element + prefix + 2nd element + ide
Nomenclature: binary acid
Hydrogen + nonmetal
Hydro + nonmetal + ic + acid
*(aq) aqueous
Nomenclature: oxyacid
Hydrogen + oxyanion
Oxyanion + ic (ate) OR ous (ite) + acid
*(aq) aqueous
Acid
Substance that yields hydrogen ions when dissolved in water
Hydrogen is written first to indicate that a substance is an acid
*To be called an acid, compound must be dissolved in water
Binary acid
Acid with only 2 elements
Format: HX
Oxyacids
Acid with hydrogen cation/ion and an oxyanion
Oxyanion prefix: per
One more oxygen than -ate
