Transcript Periodic Table Terms - Poudre School District

Bohr Model Diagrams
of atoms
Part 3 of Atomic Structure
Bromine atom…needs one
electron to have an octet in
outer shell
Krypton atom…very stable
and nonreactive because it
has a full octet
Special Family Names on the Periodic Table
Alkali Metals = hot orange
Alkaline Earth Metals = Faded Blue
Transition Metals = Indigo
Other Metals = Baby Blue
Semimetals/Metalloids = pink
Halogens = Yellow
Noble Gases = Pumpkin Orange
Other Nonmetals = Green
ATOMIC STRUCTURE
Electrons are arranged in Energy Levels or
Shells around the nucleus of an atom.
•
first shell
a maximum of 2 electrons
•
second shell
a maximum of 8 electrons
•
third shell
a maximum of 8 electrons
Electrons in larger shells have
higher energy levels
• 1st shell (corresponds to period 1 on
periodic table): lowest energy level
• 2nd shell (period 2)
• 3rd shell (period 3)
• ….
• 7th shell (period 7): highest energy level
Drawing Bohr Model Diagrams
• You must know the # of protons, neutrons, and electrons
• Draw protons (p+), (n0) in circle (i.e. “nucleus”)
• Draw the number of energy levels or shells needed (the same
as the period it is found in)
• Draw dots for electrons into the shells (order of filling is 2,8,8,2
for the first 20 elements
He
p+
2
2 n0
Li
Li shorthand
3 p+
4 n0
3 p+
4 n0
2e– 1e–
Be
B
Al
4 p+
5 n°
O
5 p+
6 n°
13 p+
14 n°
Na
8 p+ 2e– 6e–
8 n°
11 p+ 2e– 8e– 1e–
12 n°
ATOMIC STRUCTURE
There are at least two ways to represent the
electron arrangement of an element or compound;
1.
Bohr Models: nucleus and concentric rings
2.
Electron Configuration: summary of # of
electrons in each shell like 2,8,8, 1 for potassium (K)
ELECTRONIC CONFIGURATION
Write the electronic configuration for the following
elements;
a)
Ca
40
b)
Na
20
2,8,8,2
d)
Cl
35
17
2,8,7
23
11
c)
2,8,1
e)
Si
28
14
2,8,4
O
16
8
2,6
f)
B
11
5
2,3
SUMMARY
1. The Atomic Number of an atom = number of
protons in the nucleus.
2. The Atomic Mass of an atom = number of
Protons + Neutrons in the nucleus.
3.
The number of Protons = Number of Electrons.
4.
Electrons orbit the nucleus in shells.
5.
Each shell can only carry a set number of electrons.