Explain the following observations There are alwaysgaps to railway
lines
The bulb of a taboratory thermom
enter should not be held using
it to measure the temperature of
ŭ substance
When a clinical thermometer is us
ed, it is sterilized to alchol before
It is used again
solar panels are always painted be
ack​

confused

confused             hewdejdnjnjsnd

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.