Problem 57E
Which electrons experience a greater effective nuclear charge: the valence electrons in beryllium or the valence electrons in nitrogen? Why?
Isotopes Isotopes vary in the number of neutrons and therefore have different masses but remain the same element Isotopes are named by their masses, for example carbon 14 has one more neutron than carbon 13 The mass of an element on the periodic table is an average of all of its isotopes and their concentrations in nature, this is called the average molar mass Average molar mass = Σ (mass of each isotope) x (% abundance/ 100) The periodic table Each column has similar properties and is called a group (or family) Each row of the periodic table is called a period The table has 18 groups and 7 periods Metals: on the left side of the periodic table conduct electricity malleable and ductile have luster, mostly solid Metalloids: located on the zig-zag line on the right side of the periodic table look like metals but behave like non-metals Nonmetals: located on the right of the periodic table don’t conduct electricity not malleable or ductile no luster mostly gasses with few liquids or solids Parts of the periodic table Main group elements: columns 1,2 13-18 Transition metals: columns 3-12 Inner transition: located below the periodic table, really within the center of the table Alkali metals: column 1, except H Alkaline earth metals: column 2 Halogens: column 17 (7a) Noble gasses: 18 (8a) “inert gasses” Lanthanides: inner transition row 1 Actinides: inner transition row 2 Compounds There are 2 types of compounds: molecular compounds- composed of molecules of non- metals, cov