Sherman • Chem V20
Chapter 4
Atom:
All atoms of the same element have the same mass, and other properties that
distinguish them from other elements.
Atoms can only combine in whole-number ratios.
Three subatomic particles make up atoms:
Subatomic
particle
Charge
Size
Location
Electron
Proton
Neutron
Charges interact by attracting or repelling:
(+) (+):
(+) (-):
(-) (-):
How do we know the charge, size and location of these components?
Plum pudding model of atom:
Ernest Rutherford’s gold foil experiment:
Nuclear model of atom:
Sherman • Chem V20
An element is defined by Z, its atomic number:
Dmitri Mendeleev organized the elements by Z in a table, and noticed
repeating patterns in their properties – this is known as the periodic law.
Elements on the periodic table can be classified as such:
Metals:
Nonmetals:
Metalloids:
Example:
Example:
Example:
The periodic table can be further divided, too:
Alkali metals:
Alkaline earth metals:
Halogens:
Noble gases: