October 4 , 2011 The Periodic Table and Some Atomic Properties
9.1 – Classifying the Elements: The Periodic Law and the Periodic Table
Periodic Law: when the elements are arranged in order of increasing atomic mass, certain
sets of properties recur periodically.
Molar Volume = molar mass x 1/d (cm /g)
Restated Periodic Law: similar properties recur periodically when elements are arranged
according to increasing atomic number.
Description of a Modern Periodic Table: The Long Form
18 groups of elements: arranged in order of increasing atomic number from left to right
First 2 blocks: s block and p block (constitute the main group elements)
d block constitutes the transition metals
f block constitutes the inner transition metals; lanthanides and actinides
9.2 – Metals and Nonmetals and Their Ions
Characteristics of Metals:
Good conductors of heat and electricity
Malleable and ductile
Moderate to high melting points
Characteristics of Non-Metals:
Nonconductors of heat and electricity
Solids and gas at room temperature
Metalloids: elements that look like metals, may behave like metals but have some
Have the maximum number of electrons permitted in the valence shell of an atom.
Very difficult to alter, high degree of chemical inertness to the noble gases
Main Group Metal Ions:
Group 1 and 2 – the most active metals
Differ from those of the noble gas of the preceding period by only one or two
Metals tend to lose electrons to obtain electron configurations of noble gases
Main Group Nonmetal Ions:
Group 17 and 16 – the most active nonmetals
One and two electrons fewer than the noble gas
Gaining the appropriate numbers of electrons
Hydrogen does not have a definite place in the periodic table October 4 , 2011 The Periodic Table and Some Atomic Properties
Group 1; even though it is a nonmetal and appears to have some metallic when
subjected to pressures
Hydrogen does not resemble the halogens very much, as it is a reducing agent
9.3 – Sizes of Atoms and Ions
Internuclear distance; between the nuclei of two atoms joined by a chemical bond.
9-12: Why is there an uncertainty when it comes to the exact size of an atom?
- This uncertainty is due to the electron cloud which surrounds the atom; as it has
no fixed limit
Covalent Radius: one-half the distance between the nuclei of two identical atoms joined by
one single covalent bond.
Ionic Radius: the dis