1. Elements of the periodic system are divided into three groups of metals, nonmetals, and metalloids. Metals in the periodic table are separated of nonmetals by metalloids. Metals are located on the left side and the nonmetals on the right side of the periodic table. On a periodic table often is showed a stair-step line from boron to polonium which represents metan-nonmetal border. The only exception is hydrogen that is nonmetal although it is situated on the left side.
2. The most numerous elements in the periodic system are metals. At the moment, there are a total of 94 metals. There are 38 transition metals, 15 lanthanides, 15 actinides, 6 alkali metals, 6 alkaline earth metals, and 14 post-transition Metals. As regarding nonmetals, their number in the periodic table is 17 and there are 7 metalloids.
3. Metal: I would choose a copper wire, made as the name suggests from a copper that has the ability to perfectly conduct electricity.
Metalloid: I would choose a smartphone that contains computer chips made from silicon that has the property of a semiconductor.
Nonmetal: I would choose a camera flash that contains xenon, a gas which produces a white flash light when it is electrically excited.
4. Boron is a metalloid with the chemical symbol B and a serial number 5. In the periodical system, it is located in the 13th group and 2nd period.
Silicon is a metalloid with the chemical symbol Si and a serial number 14. In the periodical system, it is located in the 14th group and 3rd period.
Antimony is a metalloid with the chemical symbol Sb and serial number 51. In the periodical system, it is located in the 15th group and 5th period.