Download Electron Configurations and the Periodic Table

Electron Configurations and the
Periodic Table
•The electron configuration of an atom’s highest
occupied energy level generally governs the atom’s
chemical properties (the highest occupied level of
the noble gases contain stable octets – outer s and p
orbitals are completely filled with 8 electrons.
•The exception is helium (2 electrons in highest
occupied energy level).
•Review valence electrons.
Periods and Blocks of the Periodic
Table
•The elements are arranged vertically in the periodic
table (groups) and horizontally (periods).
•The length of each period is determined by the
number of electrons that can occupy the sublevels
in that period.
•The period of an element can be determined from
its electron configuration.
•Example: Arsenic, As, has the electron
configuration [Ar]3d104s24p3.
•The highest occupied energy level is n=4 so As is in
the 4th period.
Electron configuration is [Kr]4d55s1.
•Based on the electron configuration of the
elements, the periodic table can be divided into four
blocks, the s, p, d, and f blocks.
•The name of each block is determined by whether
an s, p, d, or f sublevel is being filled in successive
elements of that block.
The s-Block Elements: Groups 1 and 2
•Elements in the same group share similar chemical
properties.
•Elements in groups 1 (alkali metals) and 2
(alkaline-earth metals) are chemically reactive.
•The outermost energy level in an atom of each
Group 1 element contains a single s electron. This
electron is lost with ease which helps to make these
metals extremely reactive.
•The outermost energy level in an atom of each
Group 2 element contains 2 s electrons. This makes
them slightly less reactive.
•Group 1 elements have a silvery appearance and
are soft enough to cut with a knife.
•They combine vigorously with most nonmetals.
•They are extremely reactive with air or moisture
and must be stored in kerosene.
•Group 2 metals are harder, denser, and stronger
than group 1 metals.
•They are also less reactive.
•Although they are less reactive than alkali metals,
they are too reactive to be found in nature as free
elements.
Calcium
Barium
Hydrogen and Helium
•Special cases in the classification of elements.
•Hydrogen is located above Group 1 but has unique
properties.
•Helium has configuration like Group 2 but is in
Group 18 due to chemical stability.
The d-Block Elements: Groups 3-12
•The d-block elements (transition metals) have
metallic properties.
•They are good conductors of heat and have a high
luster.
Copper
Mercury
Tungsten
•These elements are less reactive than the
elements in Groups 1 and 2.
• Some are so unreactive that they do not easily
form compounds, existing in nature as free
elements.
•Palladium, platinum, and gold are among the
least reactive of all the elements.
Palladium
Platinum
Gold
The p-Block Elements: Groups 13-18
•The properties of these elements vary greatly
because the p-block consists of nonmetals, metals,
and metalloids.
•Group 17 (halogens) are the most reactive
nonmetals.
•They react vigorously with most metals to form
salts.
Chlorine
Iodine
Bromine
•The metalloids have properties of metals and
nonmetals.
•They are the most brittle solids.
Silicon
•The metals are harder and denser than the metals
in Groups 1 and 2, but softer and less dense than
transition metals.
•With the exception of bismuth, these metals are
sufficiently reactive to be found in nature only in the
form of compounds.
•Once obtained as free metals, however, they are
stable in the presence of air.
Bismuth
Aluminum
The f-Block Elements: Lanthanides
and Actinides
•Located between Groups 3 and 4 in the 6th and 7th
periods.
•Lanthanides are shiny metals similar in reactivity
to the Group 2 metals.
Cerium
Europium
•Actinides are radioactive.
•The first four have been found naturally on Earth
and the remaining actinides were made in a
laboratory.
Uranium
Thorium