Chapter 18
•Lesson 3 Part
•The Periodic Table
Dmitri Mendeleev
•Dmitri Mendeleev (1869, Russian)
–Organized elements by increasing atomic
mass.
–Predicted the existence of undiscovered
elements.
Henry Mosely
•Henry Mosely (1913, British)
–Organized elements by increasing atomic
number. One proton and electron are added
to each element as you go across the table.
–Fixed problems in Mendeleev’s
arrangement.
Metallic Character
1
2
3
4
5
6
7
•Metals
•Nonmetals
•Metalloids
Metallic Character
•Metals- good conductors of heat and
electricity, Malleable (most metals can be
hammered into thin sheets)
•Nonmetals- gases that are poor
conductors of heat and electricity at room
temperature, Brittle (breaks easily)
•Metalloids- Conduct heat and electricity
better than nonmetals but not as well as
metals, Can be shiny or dull , Solids
Table Sections
1
2
3
4
5
6
7
•Representative Elements
•Transition Metals
•Inner Transition Metals
Table Sections
Overall Configuration
1
2
3
4
5
6
7
Lanthanides - part of period 6
Actinides - part of period 7
Columns & Rows
•Group (Family)
•Period
1
11
22
33
44
55
66
77
2
3
4
5
6
7
8
9
10 11 12
18
13 14 15 16 17
Terms
•Periodic Law
–Properties of elements repeat periodically
when the elements are arranged by
increasing atomic number.
–Moving from left to right in a row of the
periodic table, metallic properties decrease.
Terms
•Valence Electrons
–e- in the outermost energy level
•Atomic Radius
•First Ionization Energy
–energy required to remove an e- from a neutral
atom
Periodic Trends
•Atomic Radius
–Increases to the LEFT and DOWN
1
2
3
4
5
6
7
Periodic Trends
•First Ionization Energy
•Increases to the RIGHT and UP
1
2
3
4
5
6
7
Periodic Trends
•Group # = # of valence e- (except He)
–Families have similar reactivity.
•Period # = # of energy levels
1A
1
2
3
4
5
6
7
8A
2A
3A 4A 5A 6A 7A
Orbital
•Region where there is 90% probability of
finding an electron.
•Can’t pinpoint the location of an electron
•Density of dots represents degree of
probability.
Orbital
•Orbitals have different shapes
Energy Levels
•Electrons can only exist at certain energy
levels.
•Low energy levels are close to the
nucleus.
•Each energy level (n) can hold 2n2
electrons.
Bohr Model Diagrams
•Simplified energy levels using Bohr’s idea of
circular orbits.
Lithium
Atomic #: 3
Mass:
7
# of p:
# of e:
# of n:
3
3
4
e-
en np n
pn p
e-
Can replace with:
3p
4n
Maximum eLevel 1
Level 2
Level 3
Level 4
2e8e18e32e-
Bohr Model Activity
•
•
•
Choose a number between 1 & 50.
Find your element by the atomic number you
picked.
Make a Bohr Model diagram for your element
on a piece of cardstock (make sure you put
your name on it because you will be turning it in
for a grade).
– Round off the mass listed on the table and
subtract the atomic # to find the # of neutrons.
– Abbreviate the # of ‘p’ and ‘n’ in the nucleus.
•
I have the card stock, yarn, and electrons,
protons and neutrons (cereal)