Ductile and malleable properties of metal
When a force is applied to a metal, the layer of metal atoms is pushed to change the position of the atom, but free electrons move to maintain the bond between free electrons and metal atoms. Therefore, the slip layer does not fall off and the regularity of the atomic arrangement does not change either.
The features of metal bonding
When you hit the lead with a hammer, it spreads thinly, but when you hit a salt crystal it breaks. Why?
Ion binding crystals do not stretch, they just break.
Unlike metal, salt is a substance that is tightly bound in the fixed position of cations (Na+) and anions (Cl-). Therefore, if you hit the salt crystals with a hammer, layers with the same polarity are created and push each other. But, metal do not break because electrons move and maintain bonding between metal cations.