Transcript A. Abundance of Elements

Lessons 3.1, 3.2A, 3.3
Period 1
Group 7
Lesson 3.1: The Elements
A. Abundance of Elements
 9 elements account for about 98% of the Earth’s
crust, ocean and atmosphere
 All materials in the universe can be broken down to
100 different elements
 All elements have symbols
Lesson 3.1: The Elements
What is the symbol for the element lead?
Answer: Pb
Lesson 3.1: The Elements
These are the some of the abundant
elements that are found in Earth.
He
Fe
N
C
Lesson 3.1: The Elements
B. Names and Symbols for the Elements
-each element has a name and a symbol
- usually consist of the first two letters of the
element name.
- the elements are named in different ways
- some elements are named after scientists, or
where the element was found.
- some elements are named by their word
origin.
Lesson 3.1: The Elements
Example:
How are most elements named?
Answer: Elements are usually named by
their word origin, founder, or places they
were found.
Lesson 3.2:
Atoms and Compounds
Dalton’s atomic theory:
-Elements are made up of atoms
-all atoms of a element are identical
-atoms of one element can combine with atoms
of other elements to form compounds
-atoms are indivisible in chemical processes
Lesson 3.2:
Atoms and Compounds
Example:
What does a given compound always
contain?
Answer: It contains the same proportions
of elements
Lesson 3.2:
Atoms and Compounds
This is the evolution of atomic theory
3.3 Atomic Structure
•To
learn about the terms: isotope, atomic number
and mass number
•To understand Rutherford’s experiment
3.3 Isotopes
Isotopes are atoms with the same
number of protons but different number
of neutron.
 A particular isotope is represent by the
symbol

3.3 Isotopes
Ex: what do Z, A and X stand for?
-> A stands for the mass number
Z stands for the atomic number
X stands for the element’s symbol
3.3 Atomic structure
Experiments by JJ. Thomson showed that
atoms contain electrons
 Ernest Rutherford showed that atoms
have internal structure
 The nucleus is at the center of the atom
 Electrons move around the nucleus

What does nucleus contain?
-> Nucleus contain proton ( positive
charged ) and neutrons ( uncharged)

Ex : Atomic structure of Uranium
(U)
References
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http://www.triumf.info/common/images/mids/vt4_hatom
_450.jpg
http://www.corrosionsource.com/handbook/periodic/pe
riodic_table.gif
http://web1.caryacademy.org/chemistry/rushin/StudentP
rojects/ElementWebSites/uranium/properties.htm
Quiz
1.
2.
3.
4.
5.
What did the experiments of J.J
Thomson show?
How many atoms does a microscopic
have?
What is the law of constant
composition?
What is Dalton’s atomic theory?
What are the charges of neutrons and
protons?