Download The Periodic law

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts
no text concepts found
Transcript
THE PERIODIC LAW
Chapter 5
DMITRI MENDELEEV
 First person to create a periodic table
• Periodic: repeating in pattern
 Mendeleev organized elements by increasing atomic mass
 Grouped elements with similar properties
HENRY MOSELEY
 Arranged the periodic table by increasing atomic number
 Periodic Law: the physical & chemical properties of the elements
are periodic functions of their atomic numbers
• When elements are arranged by increasing atomic number, elements
with similar properties appear at regular intervals
MODERN PERIODIC TABLE
 An arrangement of the elements in order of their atomic numbers
so the elements with similar properties fall in the same column or
group
PERIODS
 Horizontal rows
 7 periods
PERIODS
 Length of the period is determined by the number of electrons
that can occupy the sublevels being filled by that period
Period
# Elements in
Period
Sublevels
1
2
1s
2
8
2s2p
3
8
3s3p
4
18
4s3d4p
5
18
5s4d5p
6
32
6s4f5d6p
7
32
7s5f6d7p
GROUPS
 Vertical columns
 18 groups
REGIONS OF THE
PERIODIC TABLE
COLORS ON THE PERIODIC
TABLE
 Indicate the state of matter at room temperature
•
•
•
•
BLACK: solid
RED: gas
BLUE: liquid
WHITE: synthetic/man-made
BLOCKS
S-BLOCK
 Groups 1 & 2
 Reactive metals
 Notice:
• Li= [He]2s1
• Na= [Ne]3s1
 Group 1 (Alkali Metals) = ns1
 Group 2 (Alkaline Earth Metals) = ns2
HYDROGEN & HELIUM
 Special cases
 H = 1s1
• Does not share properties with group 1
 He = 1s2
• Part of group 18 because it’s first energy level is full with 2 e-s
• Chemically stable like the noble gases
P-BLOCK
 Groups 13-18 (except He)
 All contain 2 ns electrons
 Valence electrons = group # minus 10
• Ex. Group 17 minus 10 = 7 valence electrons
 Halogens (group 17): most reactive nonmetals because they are one
electron short of a full outer shell
 Noble gases (group 18): unreactive because they have a full outer shell
 Metalloids: semiconducting elements
MAIN-GROUP ELEMENTS
 s & p blocks
D-BLOCK
 d-block groups don’t necessarily have identical outer electron
configurations
 The sum of the outer s + d electrons = group #
• Ex. Group 10
Ni = [Ar]3d84s2
Pd = [Kr]4d105s0
Pt = [Xe]4f145d96s1
 Transition elements: d-block elements; metals with typical metallic
properties
F-BLOCK
 Lanthanides
 Actinides
 Involve filling 4f & 5f orbitals
PERIODIC/GROUP TRENDS
 As you go across a period or down a group, trends can be
observed in:
•
•
•
•
•
•
Valence electrons
Atomic radii
Ionization energy
Electron affinity
Ionic radii
Electronegativity
VALENCE ELECTRONS
 Electrons available to be lost, gained, or shared in the formation
of chemical compounds
 Main-group elements: valence electrons are in the outermost s & p
sublevels
• Correspond with the group number minus the transition elements
• Ex. Group 1 = 1 valence electron
Group 13 = 3 valence electrons
VALENCE ELECTRONS
 Periodic Trend: as you go across a period, the # of valence
electrons increases by 1
 Group Trend: as you go down a group, the # of valence electrons
stays the same (for main-group elements)
Related documents