Answer: a)
: Decomposition
b)
: double displacement
c)
: Synthesis (Combination)
d)
: redox
Explanation:
Decomposition is a type of chemical reaction in which one reactant gives two or more than two products.

A double displacement reaction is one in which exchange of ions take place.

Synthesis reaction is a chemical reaction in which two reactants are combining to form one product.

Redox reaction is a type of chemical reaction in which oxidation and reduction takes place in one single reaction. The oxidation number of one element increases and the oxidation number of other element decreases.

Answer:
c, maybe d, and I think b.
Explanation:
Im sorry if wrong
Metallic bonding
The particles in a metal are held together by metallic bonds.
High melting and boiling points
Metallic bonds are strong and a lot of energy is needed to break them. This is why metals have high melting points and boiling points.
Conducting electricity
Metals contain electrons that are free to move in the metal structure, carrying charge from place to place and allowing metals to conduct electricity well.
Metallic bonding - Higher tier
Metallic bonding is the strong attraction between closely packed positive metal ions and a 'sea' of delocalised electrons.