Dmitri Mendeleev

Question 1

When did Mendeleev publish his periodic table?

Answer 1

A: 1869.

Why: By then enough elements had been discovered to reveal strong periodic patterns.

Question 2

How did Mendeleev arrange the elements?

Answer 2

A: By increasing atomic mass.

Why: This arrangement caused elements with similar properties to line up in columns.

Question 3

What method did Mendeleev use to organize elements?

Answer 3

A: Writing element properties on cards and rearranging them.

Why: This allowed him to easily test different arrangements to find patterns.

Question 4

What major pattern did Mendeleev discover?

Answer 4

A: Periodic repetition of properties.

Why: Elements with similar properties appeared at regular intervals when ordered by mass.

Question 5

Why did Mendeleev leave gaps in his table?

Answer 5

A: He believed undiscovered elements existed.

Why: Some patterns were incomplete, so leaving spaces preserved the pattern.

Question 6

Why were Mendeleev’s predictions important?

Answer 6

A: They proved his table was accurate when new elements were later discovered.

Why: The new elements had properties close to what he predicted.

Question 7

Which element honors Mendeleev?

Answer 7

A: Mendelevium (element 101).

Why: It recognizes his major contribution to chemistry.