Mendeleev, Moseley, and the Periodic Table

1. What major contribution did Dmitri Mendeleev make to the development of the periodic table?

• Discovered all elements
  

• Organized elements by increasing atomic number

• Arranged elements by increasing atomic mass and predicted unknown elements

• Introduced quantum mechanics to explain electron behavior

Which of the following was an important feature of Mendeleev’s periodic table?

• It included only metals

• It left gaps for undiscovered elements

• It organized elements by color

• It arranged elements in alphabetical order

How did Mendeleev predict the properties of undiscovered elements?

• He used astrology

• By observing patterns in known elements

• By conducting experiments on unknown elements

• By consulting ancient texts

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Who is credited with rearranging the periodic table by atomic number rather than atomic mass?

• Albert Einstein

• Niels Bohr

• Henry Moseley

• Dmitri Mendeléyev

What was Henry Moseley’s key discovery that led to the modern arrangement of the periodic table?

• The concept of isotopes

• The measurement of atomic numbers using X-ray spectroscopy

• The discovery of noble gases

• The identification of electron shells

How did Moseley’s work change the periodic table?

• Elements were rearranged based on atomic number

• New elements were discovered

• All elements were placed in alphabetical order

• Elements were grouped by color

What is a key difference between Mendeleev's and Moseley's periodic tables?

• Mendeleev's was organized by atomic mass, Moseley's by atomic number

• Mendeleev's had no gaps, Moseley's had gaps for missing elements

• Mendeleev's table only included gases, Moseley's included metals

• Both tables were organized alphabetically

Why is Mendeleev often given more credit for the periodic table, even though Moseley's work was crucial?

• He was the first to predict properties of unknown elements

• He discovered more elements than Moseley

• He was more famous

• He invented the concept of atoms