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Elements And Compounds
ChemistryDr. May
Atoms
An atom is the smallest part of an element that still has the properties of that element.
An atom is made up of protons, neutrons, and electrons
Atomic Inventory
Element Protons Neutrons Electrons
23
Na 11
35
Cl 17
11 12 11
17 18 17
Elements The 88 naturally occurring
elements are the “chemical alphabet” of all substances in the universe.
Elements can not be broken down by chemical or physical means to simpler substances.
Compounds And Elements
A tom s N a an d C l
Tw o o r m ore e lem en ts N a an d C l
M o lecu le N aC l
C om p ou n d Tab le S a lt
Elements And Atoms An atom is the smallest part of an
element that can enter into a chemical reaction.
22.98977 grams of sodium contains 6.02 x 1023 atoms of sodium
Compounds and Molecules The molecule is the smallest part
of a compound that still has the properties of that compound.
58.44 grams of NaCl (sodium chloride) contains 6.02 x 1023 molecules of NaCl
Elements in Galaxies 91.00% hydrogen
8.75% helium
0.25% others
Elements On Earth 49.2% oxygen (H2O, O2, CO2) 25.7% silicon (SiO2, silicates) 7.5% aluminum (Al2O3, minerals) 4.7% iron (Fe2O3, earth’s core) 3.4% calcium (CaCO3) 2.6% sodium (NaCl, Na2CO3) 2.4% potassium (KCl, K2CO3)
Earth Crust
Elements In The Earth’s Crust
Elements In The Human Body 65% Oxygen (H2O, protein) 18% carbon (RNA, DNA, protein) 10% hydrogen (H2O, protein, fat) 3% nitrogen (protein, DNA) 2% calcium (bones) 1% phosphorus (phosphate in
DNA)
Diatomic Elements Seven elements
occur as diatomic molecules.
Hydrogen (H2) Nitrogen (N2) Oxygen (O2)
Fluorine (F2) Chlorine (Cl2) Bromine (Br2) Iodine (I2)
The End This presentation was created for
the benefit of our students by the Science Department at Howard High School of Technology
Please send suggestions and comments to [email protected]