Chem Test 9 (9th) 21-22

Relationship between atomic masses of groups of three elements in which the central element had atomic mass average of the other two elements.

• Dobereiner's Triads

• Mendeleev's Triads

• Dalton's Triads

Attempts were initiated to organized chemical elements

• before the determination of correct atomic masses of elements by Cannizaro

• after successful determination of correct atomic masses of elements by Cannizaro

• none of the above

Who put forward his observations in the form of "law of octaves" ?

• Newlands

• Dobereiner

• Mendeleev

Repetition in chemical properties every eight elements if arranged by increasing atomic masses.

• Law of octaves

• Octect Rule

• Musical analogy theory

Explain the relationship between the Law of Octaves and the musical notes

How many elements did Mendeleev arrange at the time in order of increasing atomic masses ?

• 63 elements

• 92 elements

• 45 elements

According to Mendeleev

• horizontal rows are called PERIODS and vertical columns are called GROUPS

• horizontal rows are called GROUPS and vertical columns are called PERIODS

• none of the above

Newlands' arrangement of elements was called Periodic Table

• True

• False

Choose the incorrect one

• isotopes have the same electronic configuration

• isotopes have the same number of protons

• isotopes have the same number of neutrons

Isotopes of the same element have

• different physical properties

• exactly the same properties

• none of the above