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Here are 70 Questions and Answers on the Periodic Table

June 24, 2025
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  • Who is the father of the modern periodic table?
    Dmitri Mendeleev.

  • Who first classified elements?
    Dobereiner.

  • What does the modern periodic law state?
    Properties of elements are periodic functions of their atomic numbers.

  • How are elements arranged in the modern periodic table?
    By increasing atomic number.

  • How many periods are in the periodic table?
    7.

  • How many groups are in the periodic table?
    18.

  • What are vertical columns in the periodic table called?
    Groups.

  • What are horizontal rows in the periodic table called?
    Periods.

  • Which element has atomic number 1?
    Hydrogen.

  • Which is the first element in the periodic table?
    Hydrogen.

  • Which group contains the noble gases?
    Group 18.

  • What is another name for Group 1 elements?
    Alkali metals.

  • What is another name for Group 2 elements?
    Alkaline earth metals.

  • What is another name for Group 17 elements?
    Halogens.

  • How many free electrons are present in Halogen group elements?
    7.

  • What is the valency of Halogens?
    1.

  • Which group contains the most reactive nonmetals?
    Group 17.

  • Which period contains the most elements?
    6th period (32 elements).

  • Name the smallest period in the periodic table.
    1st period (2 elements – Hydrogen and Helium).

  • Which is the last element in the modern periodic table?
    Oganesson (Og).

  • How many elements are present in the modern periodic table?
    118.

  • Which element is a liquid metal at room temperature?
    Mercury.

  • Which nonmetal is a liquid at room temperature?
    Bromine.

  • Which is the lightest metal?
    Lithium (Li).

  • Which element is called the 'fuel of future'?
    Hydrogen.

  • Which is the heaviest naturally occurring element?
    Uranium.

  • Which element has the highest electronegativity?
    Fluorine.

  • Which element has the lowest electronegativity?
    Cesium.

  • Which element is used in thermometers?
    Mercury.

  • Which element is essential for respiration?
    Oxygen.

  • Which metal is found in blood?
    Iron.

  • Which gas is used in balloons and is lighter than air?
    Helium (He).

  • Which element is found in diamonds?
    Carbon.

  • Which noble gas is used in signage?
    Neon.

  • Which is the hardest naturally occurring element?
    Carbon (in diamond form).

  • Which is the most reactive metal?
    Francium.

  • Which is the most reactive nonmetal?
    Fluorine.

  • Name the nonmetal with lustre.
    Carbon (as graphite/diamond) and Iodine.

  • Which gas is used in welding?
    Argon (Ar).

  • Which noble gas is found most abundantly?
    Argon (Ar).

  • How many electrons are present in noble gases?
    Zero (they have a full outer shell).

  • Which noble gas was newly added to the periodic table?
    Oganesson (Og).

  • How many gases are found in the modern periodic table?
    11.

  • Name all noble gases.
    Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn), Oganesson (Og).

  • Which actinide is used in nuclear fuel?
    Uranium.

  • Which lanthanide is used in color TVs?
    Europium.

  • What is the atomic number of Sodium?
    11.

  • Which element is called white gold?
    Platinum (Pt).

  • Which element is also called black lead?
    Graphite.

  • Name a radioactive element found in India.
    Thorium (Th).

  • Which element has the highest specific heat?
    Hydrogen.

  • Which element has the highest ionization potential?
    Helium.

  • Which man-made actinide is used in atomic bombs?
    Plutonium.

  • Which gas is used in fluorescent lamps?
    Argon.

  • Which element is used in batteries?
    Lithium.

  • Which element is used in antiseptics?
    Iodine.

  • Which element is used in fertilizers?
    Nitrogen.

  • Which metal is used in aircraft construction?
    Aluminum.

  • Which element is used in toothpaste?
    Fluoride (from fluorine).

  • Which metal is used in galvanization?
    Zinc.

  • Which noble gases are used in lasers?
    Helium-Neon.

  • Which gas is used in fire extinguishers?
    Carbon dioxide (COâ‚‚).

  • Which element is used in semiconductors?
    Silicon.

  • Name the only nonmetal that conducts electricity well.
    Graphite.

  • How many metals are present in the modern periodic table?
    91.

  • How many nonmetals are present in the periodic table?
    17.

  • How many metalloids are there in the periodic table?
    7.

  • Which is the densest noble gas?
    Radon (Rn).

  • What is the atomic number of Silicon?
    14.

  • What is the atomic number of Oxygen?
    8.