Chem 5.1 Part 2 The Periodic Table of the Elements

What was the main idea behind Dobereiner’s Triads in the development of the periodic table?

• Elements were arranged by increasing atomic number.

• Elements were grouped in threes with similar properties.

• Elements were organized by their chemical reactivity.

• Elements were arranged by their electron configurations.

Which of the following elements is part of Dobereiner’s Triads?

• Helium

• Bromine

• Neon

• Argon

How did Newlands contribute to the development of the periodic table?

• By arranging elements in order of increasing atomic number.

• By proposing the law of octaves, where every eighth element had similar properties.

• By discovering the noble gases.

• By predicting the existence of undiscovered elements.

What was a significant feature of Mendeleev’s periodic table published in 1869?

• It was arranged by increasing atomic number.

• It included all known elements without any gaps.

• It left spaces for undiscovered elements.

• It was organized by electron configurations.

Identify the pattern Mendeleev used to predict the existence of undiscovered elements.

• He used the law of octaves.

• He observed gaps in the patterns of properties.

• He arranged elements by increasing atomic number.

• He grouped elements by their electron configurations.

Which of the following elements did Mendeleev predict based on gaps in his periodic table?

• Helium

• Gallium

• Neon

• Argon

Explain how Mendeleev’s periodic table differed from Newlands’ Octaves.

• Mendeleev arranged elements by increasing atomic number, while Newlands used atomic weight.

• Mendeleev left spaces for undiscovered elements, while Newlands did not.

• Mendeleev grouped elements by electron configurations, while Newlands used chemical reactivity.

• Mendeleev used triads, while Newlands used octaves.