Polymers

Concept: Sodium forms different types of compounds with oxygen: oxides, peroxides, and superoxides, depending on the reaction conditions and the nature of the oxygen species involved.
Oxide ion: O
Peroxide ion: O (contains an O-O single bond)
Superoxide ion: O (contains an O-O bond with bond order 1.5) Sodium (Na) is an alkali metal and typically forms ions with a +1 charge (Na ). Step 1: Determine the charges of the ions to form a neutral compound
Sodium ion: Na (charge +1)
Peroxide ion: O (charge -2) Step 2: Combine the ions to form a neutral compound (Sodium Peroxide) To balance the charges for sodium peroxide: We need two Na ions to balance the -2 charge of one O ion. Total positive charge = . Total negative charge = . The overall charge is . So, the formula for sodium peroxide is . Step 3: Analyzing the options
(1) NaO: If oxygen has a -2 charge (oxide), then Na would need a +2 charge, which is not typical for sodium. If it's Na and O , this would be a radical species, not standard sodium oxide.
(2) : This is Sodium Oxide. Here, two Na ions combine with one O (oxide) ion.
(3) : This is Sodium Superoxide. Here, one Na ion combines with one O (superoxide) ion.
(4) : This is Sodium Peroxide. Here, two Na ions combine with one O (peroxide) ion. Correct. The handwritten "NaO " near the question might be a misinterpretation or a note about superoxide, but the question asks for peroxide. The formula for sodium peroxide is .

Concept: Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons (or electron density) towards itself when forming a chemical bond. Step 1: Periodic Trends in Electronegativity
Across a Period (Left to Right): Electronegativity generally increases. This is due to increasing nuclear charge (more protons) attracting the bonding electrons more strongly, while the electrons are in the same principal energy level.
Down a Group (Top to Bottom): Electronegativity generally decreases. This is because the bonding electrons are further from the nucleus (in higher energy levels) and are shielded by more inner electron shells, reducing the effective nuclear charge experienced by the valence electrons. These trends mean that the most electronegative elements are located in the upper right-hand corner of the periodic table (excluding noble gases, which typically do not form bonds or have electronegativity defined on the same common scales). Step 2: Identifying the Most Electronegative Element Based on these trends, Fluorine (F) is the most electronegative element. It is in Period 2, Group 17 (Halogens). It has the highest value on various electronegativity scales (e.g., approx. 3.98 on the Pauling scale, often rounded to 4.0). Step 3: Comparing Electronegativity of the Options Approximate Pauling electronegativity values:
Chlorine (Cl):
Oxygen (O): (Second most electronegative)
Nitrogen (N):
Fluorine (F): (Most electronegative) The order of electronegativity for these common elements is F>O>Cl N. Therefore, Fluorine is the most electronegative element in the periodic table.

Concept: Non-stick cookware is coated with a material that has a very low coefficient of friction and is resistant to sticking, making cooking and cleaning easier. Step 1: Identifying the material for non-stick cookware The most common material used for coating non-stick cookware is Polytetrafluoroethylene (PTFE). PTFE is a synthetic fluoropolymer of tetrafluoroethylene. It is well-known by the DuPont brand name Teflon. Properties of PTFE (Teflon) relevant to cookware:
Low coefficient of friction: One of the lowest of any solid, which makes it very "slippery" and non-stick.
Hydrophobic and Oleophobic: Repels water and oils.
High-temperature resistance: Stable at typical cooking temperatures (though it can degrade at very high temperatures, above approx. or ).
Chemically inert: Does not react with food. Step 2: Analyzing the options
(1) Polyethylene terephthalate (PET or PETE): This is a polyester plastic commonly used for making beverage bottles (like water and soda bottles), food containers, and synthetic fibers (like polyester fabric). Not typically used as a non-stick cookware coating.
(2) PVC (Polyvinyl Chloride): A versatile synthetic plastic used for pipes, window frames, flooring, insulation, etc. Not typically used for non-stick cookware coatings due to concerns about thermal stability and potential release of harmful substances at cooking temperatures.
(3) Polystyrene (PS): A synthetic polymer used to make disposable cutlery, food containers (like yogurt pots, foam cups/plates - Styrofoam is a brand name for expanded polystyrene). It has a low melting point and is not suitable for cookware coatings.
(4) Polytetrafluoroethylene (PTFE): Correct. This is the chemical name for Teflon, the material widely used for non-stick cookware coatings. Therefore, Polytetrafluoroethylene (PTFE) is used to make non-stick cookware.

Concept: Polymers are large molecules (macromolecules) composed of repeating structural units called monomers. They can be classified as natural or synthetic.
Natural Polymers: Occur in nature, produced by living organisms (plants and animals).
Synthetic Polymers: Man-made in laboratories or factories, often from petroleum-based chemicals. Step 1: Analyzing the options
(1) Bakelite (Phenol-formaldehyde resin): This is one of the first synthetic plastics, made from phenol and formaldehyde. It is a synthetic polymer.
(2) PVC (Polyvinyl Chloride): Made by polymerizing vinyl chloride monomer. It is a widely used synthetic plastic (e.g., for pipes, window frames).
(3) Polythene (Polyethylene): Made by polymerizing ethylene (ethene) monomer. It is a very common synthetic plastic (e.g., for plastic bags, bottles).
(4) Protein: Proteins are complex macromolecules essential to all living organisms. They are polymers made up of repeating monomer units called amino acids, linked by peptide bonds. Proteins are naturally occurring. Examples include enzymes, antibodies, keratin (in hair/nails), collagen (in skin/bones). Step 2: Identifying the natural polymer From the analysis:
Bakelite, PVC, and Polythene are synthetic polymers.
Protein is a natural polymer. Other examples of natural polymers include:
Starch (polymer of glucose)
Cellulose (polymer of glucose, main component of plant cell walls)
Natural Rubber (polymer of isoprene)
DNA and RNA (nucleic acids, polymers of nucleotides)
Silk (a protein fiber)
Wool (a protein fiber) Therefore, Protein is a natural polymer among the given options.

Concept: Natural rubber is a polymer, which means it is a large molecule made up of repeating structural units called monomers. Step 1: What is Natural Rubber? Natural rubber is primarily obtained from the latex of the Hevea brasiliensis tree (rubber tree). Latex is a milky colloidal suspension. When processed, this latex yields solid natural rubber. Step 2: The Monomer of Natural Rubber The repeating monomer unit in natural rubber is isoprene. Isoprene is a common name for 2-methyl-1,3-butadiene. Its chemical formula is . In natural rubber, isoprene units are polymerized (linked together) primarily in a {cis}-1,4 configuration, forming polyisoprene. This specific configuration gives natural rubber its characteristic elasticity. Step 3: Analyzing the options % Option (N) (1) Ethylene ( ): Polymerizes to form polyethylene, a common plastic. Not the monomer of natural rubber. % Option (O) (2) Propylene ( ): Polymerizes to form polypropylene, another common plastic. Not the monomer of natural rubber. % Option (P) (3) Acetylene ( ): Can polymerize to form polyacetylene, a conductive polymer. Not the monomer of natural rubber. % Option (Q) (4) Isoprene (2-methyl-1,3-butadiene): This is the correct monomer unit of natural rubber. Therefore, natural rubber is basically a polymer of isoprene.