Transcript Atom

How is the Periodic
Table organized?
HON-17
BrINClHOF
Anytime these elements are not in a
compound, they exist as a diatomic
molecule
H2, N2, O2, F2, Cl2, Br2, I2
Elements are arranged:
Vertically into Groups
Horizontally Into Periods
Why?
That is what you are going
to investigate now!!!
Periodic Table
Explanation
Elements Song
What do you know
about any element
in Period 2 ?
In Group 17?
Periodic
Trends
Activity
Periodic
Table
wkst
If you looked at one
atom of every element
in a group you would
see…
Each atom has the same number of
electrons in it’s outermost shell.
[aka – valence electrons]
• An example…
The group 2 atoms all have 2 electrons
in their outer shells
Be (Beryllium)
Atom
Mg (Magnesium) Atom
• The number of outer or “valence” electrons
in an atom effects the way an atom bonds.
• The way an atom bonds determines many
properties of the element.
• This is why elements within a group
usually have similar properties.
If you looked at an atom from each
element in a period
you would see…
Each atom has the same number of
energy levels
An example…
The period 4 atoms each have 4 electron
containing shells
4th Shell
K (Potassium)
Kr (Krypton)
Atom
Atom
Fe (Iron) Atom
Each group has distinct properties
• The Periodic Table is divided into several
groups based on the properties of different
atoms.
What are 5 properties that
are unique to metals?
Do metals tend to form
positive or negative ions?
Alkali Metals
Soft, silvery colored
metals
Very reactive!!!
Alkaline Earth Metals
Silvery-White Metals
Fairly reactive
Many are found in rocks in
the earth’s crust
Transition Metals
Most are good
Conductors of
electricity
Malleable (easily
bent/hammered into
wires or sheets)
Metalloids lie on
either side of these
“stairsteps”
They share properties with
both metals and non-metals
Si (Silicon) and Ge
(Germanium) are very
important “semi-conductors”
Nonmetals
Brittle
Do not conduct
electricity
Halogens
Most are
Poisonous
Fairly reactive
Noble Gases
Unreactive
Gases at room
temperature
Jellyfish lamps made with noble
gases artist- Eric Ehlenberger
Lanthanide Series
Actinide Series
Alien Lab
Which elements have the
most similar chemical
properties?
K and Na
K and Cl
K and Ca
K and S
• size of atom
• measured from center of nucleus to outside of electron
cloud
• Gets smaller across a period due to proton(nuclear) pull
• Gets larger down a group due
to extra energy levels
Found on
Reference
Table S
Is the energy necessary to remove
one electron from a neutral atom
Explaining the trend:
•The size of the atom
•Write the symbol of the element
• Put one dot for each valence earound the symbol
•There are 4 sides
•Each side can hold 2 e-
••
•
Te
•
••
The following is the order for e-
1 2
5
8
X
7 4
3
6
Calcium
Iodine
Carbon
Hydrogen
••
••
Ca
•
•I•
••
•
•
•C •
•
H
For ions
What happens when an atom forms
a positive ion?
Loses electrons
And becomes smaller
What happens when an atom forms a
negative ion?
Gains electrons
And becomes LARGER
Magnesium ion
Fluoride ion
Oxide ion
Potassium ion
Mg
+2
••
-2
••O ••
••
•
•
•• ••
F
••
K
-1
+
What is the most reactive
nonmetal?
What is the name of the
element in Group 9, Period 6?
Electronegativity is the ability of an
atom to steal an electron from another
atom
Explaining the trend:
•Number of protons in the nucleus
• The distance from the nucleus
• Different forms of the same
element, due to bonding differences
• Only certain elements in groups 13-16
Results in different chemical and physical properties
Example - Oxygen
O2 - oxygen
Graphite
Diamond
Buckminsterfullerene
Which atom of the following
pairs of atoms have the
greatest electronegativity?
(Just use your HDCRT)
K or Ge
N or Sb
Which element forms an ion
that is larger than its atom?
1)
+2
Ca
2)
+3
Al
3)
Cl
4)
+
H
Halogen Lab
Use R.T. to determine if an element
is a solid, liquid, or gas under
certain conditions.
Gas
F2 @ 100 K
Cu @ 1400C
Liquid
K @ STP
Solid
An atom has 7 protons, 7
electrons, and 7 neutrons.
Draw its dot diagram.
Practice
Exams
Analysis by
Separation Lab