This question is incomplete because the options are missing; here are the options:
Which of the following is LESS dense than water?
The spoon
The glass
The tablets
The bubbles
The correct answer to this question is The bubbles
Explanation:
In general, the density of materials and substances affects their buoyancy. This implies in water less dense materials will float and those with higher density will sink. In the situation presented, the only element that is less dense than water are bubbles; this is shown by the movement of the bubbles as these originate in the bottom of the glass of water but they rise to the surface, which shows they are less dense than water.
Because group 1a and 2a are most reactive due to their least number of electrons in their outmost shell compared to group 8a(18)
If you do not inflate the life raft to make completely filled out, as long as you do not press or squeeze the life raft, the air inside it will be in equilibrium with the air outside the raft, and so the pressure inside the life raft will be the same atmospheric pressure, 14.7 psi.
Note that when the raft is swollen, if you punch it, the air will leave from it which means that the pressure inside is greater than the atmospheric pressure.