Elements in the modern periodic table are sequenced in order of increasing__________________?
Show answer Hide answer
Answer: C. Atomic number
Explanation
The modern periodic table organizes all known chemical elements in order of increasing atomic number. Atomic number corresponds directly to the count of protons residing inside the nucleus of an atom. Arranging elements this way aligns periodic chemical behaviors with underlying electron shell configurations. Henry Moseley discovered that atomic number is a more fundamental property for ordering elements than atomic mass. Mendeleev's earlier periodic table relied primarily on atomic mass, which led to minor ordering discrepancies. Protons determine the elemental identity and positive charge of the central atomic nucleus.
Modern chemistry and physics rely on the periodic table to predict bonding, reactivity, and material properties. Newly synthesized superheavy elements are assigned positions on the table based on their measured proton numbers. Educational curricula use periodic sequencing to teach fundamental trends in electronegativity and ionization energy. Valency varies periodically across rows and does not provide a consistent sequential ordering for the entire table. Atomic mass increases generally with atomic number, but isotope variations cause anomalies that make it unreliable. Valence electrons repeat in cyclical patterns down groups, making them unsuitable for sequential table progression.
Related questions
Q1. Successive members of a homologous series differ in mass by a constant amount.
Show answer Hide answer
Answer: A. 14amu
Successive members of a homologous hydrocarbon series differ chemically by the addition of a methylene group. A methylene group consists of one carbon atom and two hydrogen atoms bonded together in a chain. Calculating t...
Q2. The oxidation state of chromium in K2Cr2O7 is____________________?
Show answer Hide answer
Answer: B. 6
In potassium dichromate, each potassium atom carries an established oxidation number of plus one. Each oxygen atom in the formula is assigned a standard oxidation number of minus two. Balancing the overall neutral charge...
Q3. Conductivity in electrolytic solutions is attributed to the movement of _____________________?
Show answer Hide answer
Answer: B. ions
Conductivity in electrolytic solutions depends entirely on the physical migration of dissolved cations and anions. When salts dissolve in water, they dissociate into freely moving charged ions that carry electrical curre...
Q4. During an isothermal process, which condition holds?
Show answer Hide answer
Answer: C. temperature of the system remains constant
An isothermal thermodynamic process is defined specifically by maintaining a constant temperature throughout. Because the temperature remains unchanged, there is zero net change in internal energy for an ideal gas. Heat...
Q5. Pig iron contains carbon at a concentration level of___________________?
Show answer Hide answer
Answer: B. 2.5 — 4.5%
Pig iron is the crude intermediate metal produced directly from the reduction of iron ore in blast furnaces. The molten iron absorbs significant amounts of carbon from the coke fuel during the smelting process. Chemical...
Q6. Which reaction occurs in a blast furnace during iron smelting within the 400°C–600°C temperature range________?
Show answer Hide answer
Answer: D. Fe2O3+ 3CO——–> 2Fe+ 3CO2
In the upper and cooler region of a blast furnace, carbon monoxide acts as a reducing agent. This region operates within the four hundred to six hundred degree Celsius temperature range. Carbon monoxide successfully redu...