Beta radiation / decay would likely occur when the ratio of protons to neutrons is below the band of stability.
Answer:
14) The edge dislocation is more plastic than the screw dislocation
15) So as to form kinks that are fast moving
Explanation:
14) Edge and screw dislocations are the two main types of mobile dislocations
The three dimensional core of the screw dislocation prevents the slipping of the layers (one over the other) in a BCC metal such that kinks are required to be formed first by thermal activation (heating) in order. The kinks are edge dislocation that move such that the screw dislocation moves forward
Hence, the edge dislocation is more plastic than the screw dislocation
15) The three dimensional structure of a screw dislocation acts like a wedge which resists the slipping of the layers in the BCC structure such that the screw dislocation needs to be highly thermally activated forming kinks before the surrounding layers can move.
An ionic bond is composed of a cation and anion, which are charged ions. You cannot have atoms with ionic bonds, because there is no opposite attraction between charges due to atoms having a net nuclear charge of zero. Therefore, a cation and anion would most likely be joined by an ionic bond.