Metals and Non - Metals

Silver has multiple valuable uses that make it precious. It is extensively used in jewelry due to its luster and workability. Silver is also the best reflector of visible light, making it ideal for mirrors. Both applications are major uses of silver, though its reflectivity makes mirrors the more technically significant use.

When metals react with water, they undergo a chemical reaction that produces two products: a metal hydroxide and hydrogen gas. For example, sodium reacts with water to form sodium hydroxide and hydrogen gas. This is a characteristic reaction of reactive metals like alkali metals and some alkaline earth metals.

Boron and silicon exhibit properties intermediate between metals and non-metals, making them metalloids. They have characteristics of both - they are semiconductors, have intermediate electrical conductivity, and can behave like metals or non-metals depending on conditions. Metalloids form the staircase line on the periodic table.

Noble metals are characterized by their exceptional resistance to corrosion and oxidation. Gold, silver, and platinum are noble metals that do not react with air (do not tarnish easily), water, or most acids. This inert nature is why they remain valuable and don't degrade over time, making them 'noble' or unreactive.

Graphite is an allotrope of carbon that contains delocalized electrons, which allows it to conduct electricity, unlike most other non-metals.

Both gold and silver are considered noble metals due to their high resistance to chemical reaction and corrosion.

The six commonly recognized metalloids are Boron, Silicon, Germanium, Arsenic, Antimony, and Tellurium.

Gallium has an unusually low melting point of about 30°C (86°F), which is near room temperature. This means gallium will melt in your hand. Sodium and potassium have low melting points but not as low as gallium, while sulfur is a non-metal. Gallium's low melting point makes it useful in high-temperature thermometers.

Diamond is an allotrope of carbon where atoms are arranged in a rigid tetrahedral crystal lattice, making it the hardest known natural substance.

The classification of elements into metals and non-metals is standard in chemistry. While exact counts can vary slightly based on the definition of metalloids, 95 metals and 17 non-metals is a commonly accepted approximation for the 118 elements.