What is a fluid ability to excert an upward force on an object

This is how zirconium appears in the periodic table. rounded to the nearest whole number, how many electrons are in an atom of zirconium?

Will you chech and finish these for me, because i am stumped with them.

Although longitudinal waves can travel through all media types what is the disadvantage of this type of wave transmission? a) he efficiency of he wave transmission is greatly diminished as the media becomes less dense b) the oscillation of one set of particles has a huge impact on neighboring particles c) particles become too close together as they bump into each other making it more likely to hit other particles down the line