The Society of Automotive Engineers has established an accepted numerical scale to measure the viscosity of motor oil. For example, SAE 40 motor oil has a higher viscosity than an SAE 10 oil. Rank the following hydrocarbons by their expected viscosity.

a. CH3CH2CH2CH2CH3
b. CH3CH2(CH2)6CH2CH3
c. CH3CH2(CH2)11CH2CH3

the atomic mass is the bottom number on the element.

-steel jelly

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.