Periodic Table Quiz

What is the main reason elements in the same group of the periodic table have similar chemical properties?

• They have the same number of electrons in the outer energy level.

• They have the same atomic weight.

• They have the same number of neutrons.

• They have the same number of protons.

Which scientist noticed that elements with similar chemical properties often occurred in groups of three, known as triads?

• Henry Moseley

• Johann Dobereiner

• John Newlands

• Dmitri Mendeleev

What did John Newlands call his observation that every eighth element had similar properties when arranged by increasing atomic weight?

• Law of Triads

• Law of Octaves

• Periodic Law

• Atomic Theory

What was a major problem with Newlands' Law of Octaves?

• It did not account for isotopes.

• It grouped elements with different properties together.

• It was based on atomic number.

• It did not include noble gases.

What was one of the key innovations Mendeleev introduced in his periodic table?

• Arranging elements by atomic number

• Grouping elements by color

• Leaving gaps for undiscovered elements

• Using symbols for elements

Why did Mendeleev sometimes switch the order of elements in his periodic table?

• To align with Newlands' Law of Octaves

• To match their physical properties

• To arrange them by atomic number

• To fit the patterns of other elements in the same group

In the modern periodic table, elements are arranged in order of what?

• Number of neutrons

• Chemical reactivity

• Atomic weight

• Atomic number

What is one major difference between Mendeleev's periodic table and the modern periodic table?

• Mendeleev's table included noble gases.

• The modern table includes group zero, the noble gases.

• The modern table is arranged by atomic weight.

• Mendeleev's table was arranged by atomic number.