Download Unit 4 Compounds, Naming, Formula Writing

Unit 4
Compounds, Naming,
Formula Writing
Accelerated Chemistry
4.1
Molecule: Smallest unit of a covalently bonded
compound.
Molecular Compounds: Compounds composed of
nonmetal atoms and formed by the sharing of
valence electrons.
4.1
Characteristics of Molecular Compounds
Representative Particle
Molecule
Type of Elements
Nonmetals
Physical State
Solid (C12H22O11), Liquid (H2O), Gas (CO2)
Melting Point
Low (Usually Below 300°C)
4.1
4.2
Ions: atoms or groups of atoms that have a positive or
negative charge.
Cation: An ion with a positive charge, formed by the loss of
electrons, usually metals. Ex. Na+
Anion: An ion with a negative charge, formed by the gain of
electrons, usually nonmetals. Ex. ClIonic Compounds: Compounds composed of metals and
nonmetals formed by the transfer of valence electrons.
4.2
Characteristics of Ionic Compounds
Representative Particle
Formula Unit
Type of Elements
Metals and Nonmetals
Physical State
Solid (ex. NaCl)
Melting Point
High (Usually Above 300°C)
4.3
Chemical Formula: Shows the kinds and numbers of atoms in a compound
Diatomic Elements: 7 nonmetallic elements exist as diatomic molecules
I Bring Clay For Our New House
I2, Br2, Cl2, F2, O2, N2, H2
4.3
Molecular Formulas: shows the kinds and numbers of atoms present in a
molecule of a compound
H2O
4.3
Formula Units: For ionic compounds, the lowest whole number ratio of
ions in the compound
NaCl
4.3
The Law of Definite Proportions
In samples of any chemical compound, the masses of the
elements are always in the same proportions.
4.3
4.3
The Law of Multiple Proportions
Whenever 2 elements form more than one compound, the different
masses of one element that combine with the same mass of the other
element are in the ratio of small whole numbers.
4.3
4.4
Monatomic ions: ions consisting of only one atom.
Ionic Charges of Representative Elements
Group 1
Group 2
Group 13
Li+
Na+
K+
Rb+
Cs+
Be2+
Mg2+
Ca2+
Sr2+
Ba2+
Al3+
Ga3+
Group 14
Group 15
Group 16
Group 17
N3P3As3-
O2S2Se2-
FClBrI-
Group 18
4.4
Many of the transition metals have more than one charge.
You must know the charges and include the charge with
Roman numerals in the name.
4.4
4.4
Polyatomic Ions: ions composed of more than one atom.
Know the names, formulas, and charges for 18 of these ions.
4.4