Atoms and Molecules (परमाणु एवं अणु) Ch(3) Practice Quiz in Hindi Part – 1 || Class 9 Science Practice Quizzes in English Posted on February 28, 2025February 28, 2025 by Anshul Gupta0% 0 votes, 0 avg 0 Atoms and Molecules (परमाणु एवं अणु) Ch(3)Practice Quiz in Hindi Part – 1 || Class 9 Science Practice Quizzes in English 1 / 201. Who established the two important laws of chemical combination? A. Antoine L. Lavoisier B. John Dalton C. Democritus D. Joseph L. Proust Explanation: Antoine L. Lavoisier is credited with establishing the foundation of chemical sciences by establishing two important laws of chemical combination. 2 / 202. What is the atomicity of a molecule? A. The number of chemical bonds it can form. B. The number of atoms constituting a molecule. C. The number of electrons in its outermost shell. D. The number of atoms that can combine with it. Explanation: Atomicity refers to the number of atoms present in a single molecule of an element. 3 / 203. Which of the following is NOT a postulate of Dalton’s atomic theory? A. Atoms of a given element can have different masses and chemical properties. B. All matter is made of very tiny particles called atoms. C. Atoms are indivisible particles. D. Atoms combine in the ratio of small whole numbers to form compounds. Explanation: Dalton’s atomic theory states that atoms of a given element are identical in mass and chemical properties. 4 / 204. Which organization currently approves the names of elements, symbols, and units? A. IUPAC B. UNESCO C. ISO D. WHO Explanation: The International Union of Pure and Applied Chemistry (IUPAC) is responsible for approving the names of elements, symbols, and units. 5 / 205. What did John Dalton propose as the smallest particles of matter? A. Electrons B. Ions C. Molecules D. Atoms Explanation: John Dalton, a British chemist, proposed that the smallest particles of matter are atoms. 6 / 206. In a compound like water, what is the ratio of the mass of hydrogen to the mass of oxygen? A. 1:8 B. 1:4 C. 1:16 D. 1:32 Explanation: The ratio of the mass of hydrogen to the mass of oxygen in water is always 1:8, regardless of the source of water. 7 / 207. What is an ion? A. A molecule with an equal number of protons and electrons. B. A subatomic particle. C. A neutral atom. D. A charged atom or group of atoms. Explanation: An ion is an atom or a group of atoms that carries a net electrical charge due to the loss or gain of electrons. 8 / 208. Who among the following Indian philosophers first proposed the idea of the smallest indivisible particles of matter? A. Democritus B. Leucippus C. Pakudha Katyayama D. Maharishi Kanad Explanation: Maharishi Kanad, an Indian philosopher, postulated the concept of ‘Parmanu,’ the smallest indivisible particles of matter. 9 / 209. What is a group of atoms carrying a charge called? A. Diatomic ion B. Polyatomic ion C. Monoatomic ion D. Triatomic ion Explanation: A polyatomic ion is a charged species consisting of two or more atoms covalently bonded together. 10 / 2010. What is the Greek equivalent of the Indian concept of ‘Parmanu’? A. Element B. Compound C. Atom D. Molecule Explanation: The Greek philosophers Democritus and Leucippus proposed the concept of ‘atoms,’ meaning indivisible particles, which is similar to the Indian concept of ‘Parmanu.’ 11 / 2011. What is the Latin name for iron, from which its symbol (Fe) is derived? A. Argentum B. Aurum C. Kalium D. Ferrum Explanation: The symbol for iron (Fe) comes from its Latin name, Ferrum. 12 / 2012. Which of the following is a diatomic molecule? A. Ozone (O3) B. Oxygen (O2) C. Helium (He) D. Phosphorus (P4) Explanation: Oxygen exists as a diatomic molecule, meaning it consists of two oxygen atoms bonded together. 13 / 2013. Who suggested the use of one or two letters from the element’s name for its symbol? A. John Dalton B. Antoine L. Lavoisier C. Joseph L. Proust D. Jöns Jacob Berzelius Explanation: Jöns Jacob Berzelius proposed the use of one or two letters from the element’s name to represent its symbol. 14 / 2014. What is a negatively charged ion called? A. Atom B. Molecule C. Anion D. Cation Explanation: An anion is an ion with a negative charge due to the gain of electrons. 15 / 2015. What is the atomic mass unit (u) defined as? A. 1/12th the mass of one carbon-12 atom. B. The mass of one oxygen atom. C. The mass of one hydrogen atom. D. 1/16th the mass of one oxygen atom. Explanation: The atomic mass unit (u) is defined as exactly one-twelfth the mass of one carbon-12 atom. 16 / 2016. What is the approximate size of an atom? A. 1 picometer B. 1 nanometer C. 1 millimeter D. 1 micrometer Explanation: Atoms are incredibly small, with their size being approximately 1 nanometer. 17 / 2017. What is the ratio by mass of nitrogen to hydrogen in ammonia (NH3)? A. 14:1 B. 7:1 C. 14:3 D. 3:1 Explanation: The ratio by mass of nitrogen to hydrogen in ammonia is always 14:3, irrespective of the source of ammonia. 18 / 2018. Who stated the Law of Constant Proportions? A. Joseph L. Proust B. John Dalton C. Democritus D. Antoine L. Lavoisier Explanation: The Law of Constant Proportions, also known as the Law of Definite Proportions, was stated by Joseph L. Proust. 19 / 2019. What does the Law of Conservation of Mass state? A. Mass can neither be created nor destroyed in a chemical reaction. B. Mass can be created but not destroyed in a chemical reaction. C. Mass can be destroyed but not created in a chemical reaction. D. Mass can be created and destroyed in a chemical reaction. Explanation: The Law of Conservation of Mass states that the total mass of the reactants and products remains the same in a chemical reaction. 20 / 2020. What is the correct symbol for the element cobalt? A. Co B. cO C. co D. CO Explanation: The correct symbol for cobalt is Co, with the first letter capitalized and the second letter lowercase. Please insert your information to see your ranking अपनी Ranking जानने के लिए कृपया अपनी जानकारी भरे NamePhone Number Your score isThe average score is 0% 0% Restart quiz Category: Class 9 Science Quizzes in English
