What was johann dobereiner’s contribution to the development of the periodic table?
1)he arranged the elements according to increasing atomic mass.
2)he arranged the elements according to increasing atomic number.
3)he identified triads of elements that had similar properties.
4)he organized elements into four groups based on their properties.

Sally turns on her cellular telephone to speak to her friend who is located thousands of miles away. which of the following best describes how such a telephone is able to transmit and receive information? a. the cellular telephone transmits, receives, and encodes information using only sound waves. b. the cellular telephone transmits, receives, and encodes information using only electromagnetic waves. c. the cellular telephone transmits information by electromagnetic waves to a receiver which then encodes them and produces sound. d. the cellular telephone transmits information by sound waves to a receiver which then encodes them and produces electromagnetic waves.