Chemistry

Quartz is a mineral composed primarily of silicon dioxide (SiO2), which is its chemical name. The other options refer to different compounds unrelated to quartz.

Deuterium is an isotope of hydrogen with the same atomic number (1 proton) but a different atomic weight due to the presence of one neutron in its nucleus, unlike protium which has none. This makes option C correct.

In a neutral atom, the number of electrons equals the atomic number, which represents the number of protons in the nucleus. Knowing the atomic number directly gives the number of electrons for a neutral atom.

Vertical columns in the periodic table are called groups because they contain elements with similar chemical properties arranged in columns. Periods are horizontal rows, and lanthanoids are a specific series of elements, not columns.

German Silver, also known as Nickel Silver, is an alloy composed primarily of copper (Cu), nickel (Ni), and zinc (Zn). It contains no actual silver despite its name. The typical composition ranges from about 7% to 30% nickel, with copper making up roughly 53% to 63%, and the remainder zinc. Among the given options, Cu + Ni (option C) best represents the main components of German Silver, as zinc is not listed in any option. Therefore, option C is the most accurate choice.

Copper can be converted into gold only through nuclear reactions such as artificial radioactivity, which involves changing the atomic nucleus. Heating, electroplating, or chemical reactions cannot change one element into another.

Laughing gas is the common name for nitrous oxide, which is chemically composed of nitrogen and oxygen atoms (N2O). Therefore, the correct elements are nitrogen and oxygen.

Oxidation is defined as the loss of electrons during a chemical reaction. This is a fundamental concept in redox chemistry, where oxidation and reduction occur simultaneously.

Diamond is an allotrope of carbon, meaning it is one of the different structural forms in which carbon can exist. Other allotropes of carbon include graphite and graphene.

Nitrous oxide (N2O) is commonly known as "laughing gas" because it produces euphoric effects when inhaled. The other options are different gases or oxides not associated with this nickname.