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Terms in this set (22)
wrote the first extensive list of all known elements and distinguished between metals and nonmetals.
Jöns Jakob Berzelius
developed a table of atomic weights and introduced
letters to symbolize elements
tried to group elements into groups of 3 with
similar properties (triads)
developed a workable method to accurately
measure the atomic masses of elements.
Alexandre-Émile Beguiler de Chancourtois
arranged the elements in order
of increasing atomic weights.
proposed a "Law of Octaves" to order the elements. He
noticed that when the elements were arranged by atomic weight, certain chemical properties began to repeat themselves roughly every 8 elements.
compiled a table of 56 elements based on the periodic
properties when elements were arranged by increasing atomic weight.
produced a table
based on atomic weights but arranged
"periodically" with elements with similar
properties under each other.
discovered noble gases
listed elements in order of increasing atomic number instead of increasing
created a modern periodic table with Lanthanides and Actinides
shiny, malleable, ductile, good conductors
of energy, tend to form positive ions,
dull, brittle, bad conductors of
energy, tend to form negative ions, generally
gases or soft solids at room temperature,
found around the "stair-step" or
"zig-zag" line that divides metals and
nonmetals. They exhibit properties of both
metals and nonmetals, usually depending upon
discovered in late 19th century.
discovered first in early 1900s, found in Period 6
of table, consist of 14 elements
discovered later than lanthanides, found in Period 7 of
table, consist of 14 elements
outermost energy level contains a single s electron, metals have silvery appearance, soft enough to be cut with a knife, not found in nature as free elements
because they are so reactive.
alkaline earth metals
outermost energy level contains a pair of s electrons, harder, denser, stronger, higher melting points than Alkali Metals, less reactive, but still too reactive to be found in nature as free elements.
When grouped with s-block are called
"Main-Group". Properties vary greatly - left side are
metals, right side are nonmetals,
metalloids are in this block as well. Metals are harder and denser than s-block.
transition elements, typical metallic properties. Less reactive than s-block metals. Some are very nonreactive and do not form compounds easily. found in nature as free elements in their pure form
Lanthanides - shiny metals similar in reactivity to alkaline earth metals. Actinides - all radioactive, first 4 are natural, rest are synthetic.
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