Elements of Life Page 33
Carbon
Hydrogen
Oxygen
Nitrogen
Phosphorus
Sulfur
Calcium
Potassium
---------------------------------------------------------------------------------------------------------------------------Identify meaning and significance of…
Page 34-35
Proton
In the nucleus
Have a positive charge
Neutron
In the nucleus
Number can vary within an element (Isotopes)
Electron
Form a cloud around the nucleus
Have a negative charge
Atomic Number
Total number of protons
Written as the subscript to the left of the symbol for an element
Atomic Mass
Sum of the protons and neutrons
Written as a superscript to the left of the element’s symbol
Isotope
Atoms of the same element that very in the total number of neutrons
Radioactive Isotope
An unstable isotope
Nucleus decays spontaneously, giving off particles and energy
Are easy to detect and can be used as tracers
-----------------------------------------------------------------------------------------------------------------------------------Why electrons in first energy level have less energy than electrons in higher energy levels
Page 36
Electrons are attracted to the positively charged nucleus. Because of this, it takes work to move an
electron farther away from the nucleus. The more distant the electrons are from the nucleus, the greater
their potential energy.
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-----Distinguish between ……. and identify significance of these terms
Valence electrons
Electrons on the outermost electron shell
Valence Shells
The outer most electron shell which contain valence electrons
Page 38
-----------------------------------------------------------------------------------------------------------------------------------Define different types of chemical bonds
-Identify the role of electrons in each type of bond (covalent (polar and nonpolar), ionic, and hydrogen)
Covalent Bond
Sharing of a pair of valence electrons by two atoms
Two or more atoms held by a covalent bond represent a molecule
Can be…
Polar Covalent Bond
Electrons are not shared equally
Example: Water; hydrogen has a slight positive charge, oxygen has a slight
negative charge
Non Polar Covalent Bond
Electrons are shared equally
Example: H2 or O2
Form symmetrical molecules
Ionic Bond
Form when there is a great difference in electro negativity
Electron is stripped from one atom to the other with higher electronegativity
Attraction between oppositely charged ions (anion and cation)
Hydrogen Bond
Forms when hydrogen atom covalently bonds to one electronegative atom and is also
attracted to another electronegative atom
Usually involve elements F, O, N (phone)
Page 39-42
-----------------------------------------------------------------------------------------------------------------------------------Give an example that shows how a molecule’s shape can determine its function
Page 43
Endorphin is naturally produced and helps produce euphoria and relieves pain. Morphine and heroin are
shaped similarly to endorphin and therefore can create similar effects as endorphin does.