Properties of Groups Chapter 7 part II

Metals, Nonmetals & Metalloids

Information from the Periodic Table The number and type of valence electrons determine the group/chemical reactivity. From the periodic table one can determine the electron configuration. Certain groups have specific names.

Group IA Alkali Metals Valence electron is s1 First ionization energy is low. First ionization energy deceases as atomic radius increases. Why?

Group 2A Alkaline Earth Metals Valence electrons are s2. Higher first ionization energy than group 1A, but much lower second ionization energy.

Group 3A Group 3A Form +3 ions upon ionization Metals and semimetals aka metalloids.

Ionic Compounds How ionic or covalent a compound is depends on the placement of elements on the periodic table (hence their electron configuration). Many covalent compounds have ionic characteristics and visa versa.

Halogens Group 7A, Form -1 ions upon gaining an electron.

Nobel Gases Group 8A Complete s2p6 shell Tend not to form compounds and were formerly known as the 'inert gases.' However, a few of them (most notably xenon) have been found to form compounds with fluorine.

Diamagnetic When all electrons are paired in an atom, ion, or compound - it is said to be diamagnetic and largely unaffected (very weakly repelled) by external magnetic fields. Examples: Beryllium

Paramagnetic When unpaired electrons exist, like the case for Li below, the material is termed paramagnetic and it is attracted to a magnetic field.

This effect can be measured for various elements and compounds with an electrobalance as shown below