Transcript Atomic Structure ppt

Complete the Bubble Map by defining each term.
Atomic Structure
BEFORE….
Atomic Structure
AFTER! Elements don’t change.
Subatomic Particles
• Protons and electrons are the only particles that have
a charge.
• Protons and neutrons have essentially the same mass.
• The mass of an electron is so small we ignore it.
Protons and Neutrons make up the
Nucleus, while electrons orbit.
There can several different orbital's
and energy levels within an element
Symbols of Elements
Elements are symbolized by one or two letters.
Atomic Mass
The mass of an atom in atomic mass units (amu) is
the total number of protons and neutrons in the
atom.
Atomic Number
All atoms of the same element have the same
number of protons:
The atomic number (Z)
Atoms that have the same
number of protons but
different numbers of neutrons
are call ISOTOPES.
Isotopes:
• Atoms of the same element with different masses.
• Isotopes have different numbers of neutrons.
11
C
6
12
C
6
13
C
6
14
C
6
So with all these different
isotopes, how do we find the
average atomic mass of an
element?
Average Atomic Mass
% natural abundance is the amount of each
isotope as they occur in nature.
•
•
•
Multiply the amount given for each
element by their % abundance
Add all of the figures together from
each element
This is your Average Atomic Mass
Let’s work one out
Data gathered from a mass spectrometer
experiment:
78.92 amu 50.69% abundant
80.92 amu 49.31% abundant
1. Multiply the amount given for each element by their
% abundance
78.92 x .5069 = 40.00
80.92 x .4931 = 39.91
2. Add all of the figures together from each element
40.00 + 39.91 = 79.91 amu
What Element is this?
Bromine
Now You try
14.003 amu 94.63% abundant
15.000 amu 5.37% abundant
What is the atomic mass?
What element is this?
14.056
Nitrogen
One More
It is found that the element boron has two
isotopes. B-10 (11.811amu) is 19.91% abundant
and B-11 (10.845amu) is 80.09% abundant.
What is the average atomic mass of B?
10.946 amu