Transcript Basic Chemistry - Doral Academy High School

Basic Chemistry
CHAPTER 2
Video
 https://www.youtube.com/watch?v=9D05ej8u-gU
What are elements?
 What can you tell me about elements?
What are elements?
 Elements: The fundamental units of matter
What are elements?
 Elements: The fundamental units of matter
 What do we mean by fundamental?
What are elements?
 Elements: The fundamental units of matter
 What do we mean by fundamental?
 Necessary base or core
Elements of the Body
96% of the body is made from 4 different
elements
A Look at Matter
Elements of the Body
96% of the body is made from 4 different
elements
 Carbon (C)
 Oxygen (O)
 Hydrogen (H)
 Nitrogen (N)
Hydrogen Bomb
 https://www.youtube.com/watch?v=yEje927dygM
 https://www.youtube.com/watch?v=h7vyKDcSTaE
What are atoms?
What are atoms?
 Atoms: The building blocks of elements
Atomic Structure
What are the different parts of an atom?
Atomic Structure
Nucleus
 Protons (p+)
 Neutrons (n0)
Outside of
nucleus
 Electrons (e-)
Atomic Structure of Smallest Atoms
Atomic Structure of Smallest Atoms
 https://phet.colorado.edu/en/simulation/build-an-atom
How do we identify elements?
How do we identify elements?
Atomic number
How do we identify elements?
Atomic number: equal to the number of
protons that the atom contains
How do we identify elements?
Atomic mass number:
How do we identify elements?
Atomic mass number: sum of the protons
and neutrons
Why are atomic masses not in whole
numbers?
Protons + Neutrons right?
Isotopes and Atomic Mass
ISOTOPES!
Isotopes and Atomic Mass
Isotopes:
 Have the same number of protons
 Vary in number of neutrons
Isotopes and Atomic Mass
Close to mass number of most abundant
isotope
Atomic weight reflects natural isotope
variation
Isotopes and Atomic Mass
https://phet.colorado.edu/en/simulation/is
otopes-and-atomic-mass
Electrons and Bonding
Energy levels called
electron shells
Electrons closest to
the nucleus are most
strongly attracted
Electrons and Bonding
Bonding - interactions
between electrons in
the outer shell (valence
shell)
Full valence shells do
not form bonds
Electrons and Bonding
 How to fill the atom’s shells
 Shell 1 - maximum of 2 electrons
 Shell 2 - maximum of 8 electrons
 Shell 3 - maximum of 18 electrons
 Shell 4 - maximum of 32 electrons
 Shell 5 - maximum of 50 electrons
 Shell 6 – maximum of 72 electrons
Electrons and Bonding
Lewis Dot Structures
 Diagrams that show the bonding between atoms
 Represent the valence shell
 Carbon has 6 protons, 6 elections
 So…….4 electrons are in the
valence shell
Lewis Dot Structures
Lewis Dot Structures
Lewis Dot Structures
Rule of Eights (Octet Rule)
 Atoms are considered stable when their
outermost orbital has 8 electrons
 The exception to this rule of eights is Shell 1,
which can only hold 2 electrons
 https://www.youtube.com/watch?v=WzWkmx_14E
Electrons and Bonding
 http://www.bbc.co.uk/schools/gcsebitesize/scienc
e/add_ocr_gateway/periodic_table/atomstrucact.s
html
Radioactivity
 Radioactivity—process of spontaneous atomic decay
 What can we use this for?
Radioactivity
 Radioactivity—process of spontaneous atomic decay
 What can we use this for?
Radioactivity
 Radiometric Dating:
 Uranium

238U
to 206Pb, with a half-life of 4.47 billion
years
 235U to 207Pb, with a half-life of 704 million
years.
 Carbon
 Carbon-14 is a radioactive isotope of
carbon, with a half-life of 5,730 years
 Very short compared to other isotopes
Molecules and Compounds
 Molecule: Two or more like atoms combined chemically
 Compound: Two or more different atoms combined chemically
Molecules and Compounds
https://phet.colorado.edu/en/simulation/build-a-molecule
What are chemical reactions?
What do you remember?
What are chemical reactions?
 Atoms are united by chemical bonds
OR
 Atoms dissociate from other atoms when chemical
bonds are broken