Explain why the element nickel has a high melting point

Nickel is a metal and therefore it contains positive ions, called protons, which are surrounded by a sea of delocalised electrons, which are negative ions. There is a strong force of attraction between these positive and negative ions, and this requires a large amount of energy to break. This means that a large amount of heat energy needs to be applied to break the bonds, resulting in a high melting point.