Chemistry of Metals and Alloys

Modern coins are primarily made from base metals like copper, nickel, zinc, and their alloys (cupronickel, brass, bronze). Precious metals (gold, silver) are too expensive for circulation coins, while diamond is never used as a coinage material. Base metals provide durability, electrical conductivity for vending machines, and lower production costs.

This is an exact duplicate of question 27691 with identical content, options, and answer. Modern coins are made from base metals like copper, nickel, zinc, and their alloys rather than precious metals or gemstones.

Ag is the chemical symbol for Silver, derived from its Latin name 'Argentum'. Silver is a transition metal (atomic number 47) valued for jewelry, electronics, and antibacterial properties. Gold is Au, Copper is Cu. Note: option C has a typo - should be 'Platinum'.

Technetium (atomic number 43) was the first element to be produced artificially in 1937 by Carlo Perrier and Emilio Segrè. All naturally occurring technetium on Earth comes from spontaneous fission of uranium-238 or from cosmic ray interactions. It was named from the Greek 'technetos' meaning 'artificial.' Molybdenum (42) and Protactinium (91) occur naturally, while Meitnerium (109) was synthesized much later in 1982.

7075 is an aluminium alloy with zinc as the primary alloying element (5.1-6.1%), along with magnesium (2.1-2.9%) and copper (1.2-2.0%). It is known for its high strength-to-weight ratio and is commonly used in aircraft structures and other high-stress applications.

Gold's chemical symbol Au comes from the Latin word 'aurum' meaning gold. Silver is Ag (from 'argentum'), Antimony is Sb (from 'stibium'), and Gadolinium is Gd. Au is the universally accepted symbol in chemistry.

Bromine is the only non-metallic element that is liquid at room temperature (along with mercury, which is metallic). Bromine has a distinctive reddish-brown color and produces a red-brown vapor. It's a halogen element in Group 17 of the periodic table.

Pure copper has a distinctive reddish-orange metallic color that distinguishes it from most other metals. This characteristic coloration comes from copper's electronic structure and is why copper appears pinkish-orange when freshly exposed. The reddish metallic appearance is unique among common structural metals.

Beryllium is a steel-gray metal in its solid form. It has a metallic luster and appears grayish-silver, similar to other lightweight metals like aluminum or titanium but with a slightly darker tone.

The Latin word 'aurum' means 'shining dawn' or 'glowing dawn' and is the etymological origin of gold's chemical symbol Au. This is a classic example of how element symbols derive from Latin, Greek, or other ancient languages.

Stainless steel is primarily an alloy of iron (Fe) and carbon (C), with chromium and nickel as key additional elements that provide corrosion resistance. The chromium content (typically 10.5% or more) creates a protective oxide layer, while nickel enhances strength and corrosion resistance. Aluminum, tin, copper, zinc, lead, and magnesium are not primary components of standard stainless steel.

Thimerosal (spelled thimerosol in the question) is an organomercury compound containing approximately 49% mercury by weight. It was widely used as a preservative in vaccines and other medical products. Iron, cadmium, and silver are not components of thimerosal.

Carbon is the odd one out because it is a non-metallic element, while Steel (alloy), Copper, and Aluminium are all metals. Carbon exists as graphite and diamond, which are non-metallic forms.

Curium is a synthetic radioactive element with atomic number 96, and its chemical symbol is 'Cm'. The symbol is derived from its name. Copper is 'Cu', Copernicium is 'Cn' (not 'Cp'), and Caesium is 'Cs'.

Cobalt's chemical symbol is Co, derived from its German name 'Kobold'. Option A is Copper, C is Cerium, and D is Cesium. The symbol uses the first two letters to distinguish it from other elements starting with 'C'.