Aluminium is a metal:
Aluminium is a chemical element with the symbol Al and atomic number 13. It is a silvery-white, lightweight metal that exhibits excellent corrosion resistance and durability. Here are some key points to understand why aluminium is classified as a metal:

- Physical properties: Aluminium has metallic properties such as high electrical and thermal conductivity, malleability, ductility, and metallic luster. These characteristics are typical of metals.
- Atomic structure: Aluminium has a metallic bonding, which is formed by the sharing of electrons between aluminium atoms. This type of bonding is characteristic of metals.
- Electrical conductivity: Aluminium is a good conductor of electricity, which is a property commonly associated with metals. This is why aluminium is widely used in electrical wiring and power transmission lines.
- Malleability and ductility: Aluminium can be easily shaped into thin sheets and wires without breaking, indicating its malleability and ductility. These properties are also typical of metals.
- Metallic luster: Aluminium has a shiny appearance, known as metallic luster, due to the reflection of light from its surface. This is a characteristic feature of metals.

Silicon is a metalloid:
Silicon is a chemical element with the symbol Si and atomic number 14. It is classified as a metalloid, which is an intermediate category between metals and nonmetals. Here are some reasons why silicon is considered a metalloid:

- Physical properties: Silicon has both metallic and nonmetallic properties. It is a brittle, crystalline solid with a metallic luster, but it does not possess the same level of malleability and ductility as metals.
- Chemical reactivity: Silicon shares similarities with both metals and nonmetals in terms of its chemical reactivity. It can form compounds with nonmetals, similar to nonmetals, but it can also exhibit metallic characteristics by donating or accepting electrons.
- Semiconducting properties: Silicon is well-known for its semiconducting properties, which is a key characteristic of metalloids. It is the second most abundant element on Earth's crust and is widely used in the production of semiconductors, such as computer chips.
- Atomic structure: Silicon has a similar atomic structure to carbon, which is a nonmetal. It has four valence electrons, allowing it to form covalent bonds. However, it can also form ionic bonds by gaining or losing electrons.

Phosphorus is a nonmetal:
Phosphorus is a chemical element with the symbol P and atomic number 15. It is classified as a nonmetal due to the following characteristics:

- Physical properties: Phosphorus exists in several allotropes, including white, red, and black phosphorus. These forms exhibit nonmetallic properties such as brittleness, lack of luster, and poor thermal conductivity.
- Chemical reactivity: Phosphorus readily reacts with oxygen, sulfur, and other nonmetals, forming compounds. It typically gains electrons in chemical reactions, indicating a nonmetallic behavior.
- Electrical conductivity: Unlike metals, phosphorus is a

Aluminum can donate electron so Al is metal bcoz only metal can do it & phosphorus can receive electron so it is non-metal
silicon contains both nature so it is a metalloid