Vocabulary
central core of an atom
nucleus
H
Hydrogen
Number of protons in Copper
29
elements that have properties of both metals and nonmetals
metalloids
Helium
He
horizontal rows on the periodic table
periods
Pb
Lead
Number of electrons in Barium
56
This section of the periodic table includes mostly man-made elements and they are all radioactive
actinides
Oxygen
O
postively charged particles found outside the nucleus
protons
K
Potassium
Number of neutrons in a chlorine atom with a mass of 36
19
largest section of the periodic table; these elements from many compounds
transition metals
Chlorine
Cl
Place where electrons are found
electron cloud
Hg
Mercury
Number of electrons in a zinc atom with a mass of 65
30
these elements were the last to be discovered because they don't react with other elements; they are very inert and stable
noble gases
Sodium
Na
scientist who organized the elements into the periodic table
Dmitri Mendeleev
W
Tungsten
Number of neutrons in a radon atom with a mass of 222
136
These metals are very reactive and are found in Group 1A of the periodic table
alkali metals
Iron
Fe