Q1 - No, because of the friction between the edges of the blocks
Q2- forms a gaps between block 1&2 and block 3&4
Q3- they will probably move apart each other
Q4- Block 1 remain collided to block3 as well as blocks2&4
1 5 1
uhm.. you answered the x activity, that is for the 1st module activity 5 which is titled as Slide and Shake...