Atomic Structure and Periodicity

List the postulates of Dalton that continue to have significance (are retained in modern atomic theory).

Match the atomic theory statements in part A with the matching items in part B.

A nitrogen-oxygen compound is found to have an oxygen-to-nitrogen mass ratio of 1.142 g oxygen for every 1.000 g of nitrogen. Which of the following oxygen-to-nitrogen mass ratio(s) is/are possible for different nitrogen-oxygen compound(s)?

• 2.285

• 0.571

• 1.000

• 2.500

Determine, which of the following oxygen-to-nitrogen mass ratio(s) is/are also possible for nitrogen-oxygen compound. (Refer Example 2.1 No. 1 for required information)

• 0.612

• 1.713

• 1.250

• 2.856

What did Robert A. Millikan determine by observing the behavior of electrically-charged oil drops in an electric field?

What did James Chadwick discover in 1932?

Why do isotopes of an element have similar chemical properties?

Identify element X whose atoms contain 24 protons and write the symbol for the isotope with 28 neutrons

What is the mass number of an isotope of tin that has 66 neutrons and 50 protons?

What is the formula to calculate the Bohr radius?