Branches of Chemistry & History of the periodic table

What was Dmitri Mendeleev's greatest contribution to the history of the periodic table?

• He arranged all of the known elements by their atomic number
• He realised that there was a pattern of reactivity which repeated every 8 elements
• He predicted the existence (and properties) of new elements
• He identified the "law of triads" which became the groups

What was significant about the X-ray experiments performed by Henry Moseley?

• It demonstrated that all atoms contained protons in their nuclei
• It explained what made up the "missing" mass in the nucleus
• It led to the idea that electrons can only occupy specific "orbits" around the nucleus
• It allowed people to determine the nuclear charge of any atom

The periodic table is organized by the number of ______ in each element's nucleus

• neutrons
• protons
• electrons
• atoms

Who arranged the first periodic table.

• Mosely
• Einstein
• Mendeleev
• Bohr

Scientist who first grouped the elements in groups of threes (triads).

• Johann Dobereiner
• John Newlands
• Demitri Mendeleev
• Henry Mosely

What property did Newlands use to arrange his elements?                               

• atomic mass
•  number of protons 
• atomic size     
• melting point      

Why were there blank spaces left in Mendeleev's periodic table?                                              

• He didn't know what to put there.
•  Undiscovered elements not yet known.
• Multiple elements could have fit
• He forgot to add the elements in.

Moseley discovered that the ________ was the most fundamental property needed for organization.                                                 

• atomic mass
• mass number
• atomic number
• number of protons

In each square of the periodic table, the number at the bottom is the:

• atomic number

• atomic mass

• chemical symbol

• element name

Tags

NGSS.MS-PS1-1

The number at the top of each square on the periodic table is the ...

• atomic number
• atomic mass
• Chemical Symbol
• Element Name

Tags

NGSS.MS-PS1-1