Which of these was not proposed by John Dalton in 1805?

• All matter is made of atoms
• Atoms are made of protons, neutrons and electrons
• During chemical reactions, atoms rearrange themselves
• The atoms of a particular element are all identical

Tags

NGSS.HS-PS1-7

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

What property did Menedleev use to organize his first periodic table?

• atomic number
• atomic mass
• alphabetical order
• chemical properties

The periodic law states that if you organize elements by their atomic mass 

• elements will overlap
• elements will not share properties
• physical properties will remain the same.
• chemical properties will occur periodically. 

Tags

NGSS.HS-PS1-1

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

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

Which of the following models of an atom is most widely accepted as correct?

• Bohr model
• Quantum-mechanical model
• Atomic model
• Radioactive model

Why did scientists need/want to organize the elements?

• Scientists like things organized
• make it easier to understand the elements
• have one list of the known elements.
• none of the above