Locate the row containing lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). Look up these elements in the periodic table e, and click each element to reveal its
properties. Explain why Mendeleev might have grouped these elements together.

it should have an internal chamber and two thermometers sticking out of the top. the internal chamber will also be closed off from the outside.

5 structural isomers

the isomers are:

n-exane :   ch3ch2ch2ch2ch2ch3

2-methylpentane :   ch3ch(ch3)ch2ch2ch3

3-methylpentane :   ch3ch2ch(ch3)ch2ch3

2,3-dimethylbutane :   (ch3)2chch(ch3)2

2,2-dimethylbutane :   (ch3)3cch2ch3