5-2: Electron Configuration and the Periodic Table Objectives: Describe the relationship between electrons in sublevels and the length of the each period of the periodic table Locate and name the four blocks of the periodic table. Explain the reasons for the three names. Discuss the relationship between group configurations and group numbers Describe the locations in the periodic table and the general properties of the alkali metals, the alkaline-earth metals, the halogens, and the noble gases.
Transcript
5-2: Electron Configuration and the Periodic Table
Objectives:- Describe the relationship between electrons in sublevels and the length of the each
period of the periodic table- Locate and name the four blocks of the periodic table. Explain the reasons for the
three names.- Discuss the relationship between group configurations and group numbers
- Describe the locations in the periodic table and the general properties of the alkali metals, the alkaline-earth metals, the halogens, and the noble gases.
Electron
configuration?
… Remember?
Four types of sublevels?
Group: a vertical column of elements in the periodic table◦ Tells how many electrons are in the atom’s outer
shell (valence electrons) Period: a horizontal row of elements in the
periodic table◦ Length of each period is determined by the
number of electrons that occupy the energy sublevels being filled
Periods and Blocks of the Periodic Table
• Period of an element can be determined from the element’s electron configuration
• Periodic table can be divided into four sublevel blocks based on the electron configuration of elements – s, p, d, and f blocks
The s-Block Elements: Groups 1 and 2 Elements of the s-block are chemically
reactive metals Elements of Group 1:
◦ Outermost energy level contains a single s electron
◦ Alkali metals: elements of Group 1 of the periodic table (Li, Na, K, Rb, Ce, Fr)- Properties:
- Silvery appearance and soft enough to cut with a knife (in its pure state)
- Highly reactive- Combine strongly with most nonmetals
Elements of Group 2:◦ Outermost energy level contains a pair (2) electrons ◦ Alkaline-earth metals: elements of Group 2 of the
periodic table (Be, Mg, Ca, Sr, Ba, Ra)- Properties:
- Metals are harder, denser, and stronger than alkali metals- Higher melting points- Highly reactive
◦ Hydrogen and helium do not share the same properties of Group 1 and 2, respectively
Transition metals: metals with typical metallic properties in the d-block of the periodic table Properties:
Good conductors of electricity High luster Less reactive than alkali and alkaline-earth metals Some so unreactive they do not form compounds easily
The d-Block Elements: Group 3-12
Properties of the elements of the p-block vary greatly◦ Includes:
- all of the nonmetals except hydrogen and helium- all six of the metalloids (B, Si, Ge, As, Sb, Te)- the halogens- the noble gases
The p-Block Elements: Groups 13-18
◦ Halogens: the elements of Group 17 (fluorine, chlorine, bromine, iodine, and astatine)- The most reactive nonmetals- React vigorously with most metals to form salts
◦ Metalloids (semiconducting metals) - mostly brittle solids with some properties of metals and some
of nonmetals
◦ Metals of the p-block- Generally harder and denser than the s-block alkaline-earth
metals, but softer and less dense than the d-block metals- Sufficiently reactive to be found in nature only in the form of
compounds- Stable in the presence of air
Main-group elements: elements of the p-block together with elements of the s-block
Electrons fill the 4f sublevel Lanthanides are shiny metals similar to the
Group 2 alkaline-earth metals Actinides are all radioactive
◦ The first 4 have been found naturally and the remaining are known lab-made elements
