Atomic Number (Z): Number of protons in an atom (found on the bottom left of the symbol) (found on top of modified table)
Mass Number (A): Number of protons + number of neutrons (found on top left of the symbol)
Atomic Weight/Average Atomic Mass: An average of all naturally occurring isotopes (found on bottom of modified table)
Mosely: X-rays wavelength depends on proton
Becquerel: Matter containing uranium exposed photographic film
Pierre and Marie Curie: Uranium and radium
Periodic Table
Group/Column/Family: Vertical section with elements of similar properties
Periods/Row: Horizontal section based on increasing atomic number
Group 1: Alkali Metals
Group 2: Alkaline Earth Metals
Group 6: Chalcogens
Group 7: Halogens
Group 8: Noble gases/Stable octet/Inert
Empirical Formula: Simplest whole number ratio of atoms (always used in ionics)
Molecular Formula: Tells you how many atoms are actually present
Structural Formula: Shows how the elements are bonded together
Ionic: Contains a metal and nonmetal. Large electronegativity difference. Transfers electrons. Forms salts (which are usually solids)
Covalent: Contains two nonmetals with little or no electronegativity difference. Shares electrons
Azide: N3
-1
Metals: Positive ions immersed in a sea of mobile electrons
Review of Naming
Ionic:
? Always written with empirical formula (lowest whole number ratio)
? Name the metal and then name the nonmetal with an “ide” (cation then anion)
? All ionic compounds since they have a metal and a nonmetal, are salts
Ex: NaCl (Sodium Chloride), MgBr2 (Magnesium Bromide)
? Use stock system when there is more than one oxidation number
Ex: PbCl4 – Lead (IV) Chloride
? The old naming has the first oxidation as “ous” and the second as “ic”
Ex: FeCl3 (Ferric Chloride), FeCl2 (Ferrous Chloride)
? 1
st
ox. names: Iron (Ferrous), Copper (Cuprous), Tin (Stannous), Gold (Aurous), Lead (Plumbous), Cobalt (Cobaltous),
Manganese (Managnous), Mercury (Mercurous), Nickel (Nickelous), Chromium (Chromous)
? The formula for mercurous/mercury(I) is Hg2
+2
1/12th
the mass of C-12 = 1 amu or u