Lesson 2 - True or False

Electrons and protons were not discovered before the nineteenth century.

• True

• False

Atomic masses of many elements were measured accurately in the 19th century.

• True

• False

John Newlands was the first one to arrange elements in order of atomic mass.

• True

• False

John Newlands was the first one to discover the law of octaves.

• True

• False

The periodic table of Mendeleev could predict the properties of elements that had not yet been discovered.

• True

• False

Mendeleev worked with Meyer to build their version of the periodic table, which was a great improvement over Newlands's one.

• True

• False

According to the periodic table proposed by Mendeleev, argon should be placed in the same group with lithium and sodium.

• True

• False

Rutherford was the first person to find out that the nuclei of elements are positively charged.

• True

• False

According to Moseley, the order of increasing atomic numbers is always the same as the order of increasing atomic masses.

• True

• False

Physical and chemical properties could be explained based on the electron configurations of elements.

• True

• False