It has the same atomic mass but different atomic no. The atoms of a chemical element can exist in different types. (iv) Identify the element. The nucleus is made up of protons and neutrons and the electrons revolve around the nucleus. These two ways include writing a nuclear symbol or by giving the name of the element with the mass number written. The different atoms of the same element having same atomic number but different mass numbers. Isotopes are members of a family of an element that all have the same number of protons but different numbers of neutrons. Question 33. Question 11. Question 14. O Isotopes differ in the number of neutrons each contains. (CBSE 2015) As we all know that atoms are made up of electrons, protons, and neutrons. So, we can say that isobars are those elements that have a different atomic number but the same mass number. (a) How many neutrons are present in C-14 isotope of carbon ? Answer: Answer: Explain. Different isotopes of an element generally have the same physical and chemical properties. (c) These isotopes differ in their masses. 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These atoms are the isotope called carbon-13. Isotopes have the same atomic number but different atomic mass numbers: Hence, the statement saying; "Isotopes have the same atomic number but different atomic mass numbers", is a true statement. These atoms are the isotope called carbon-13. This obstruction must be : (iii)Positively charged : Alpha particles have positive charge. Isotopes of any given element all contain the same number of protons, so they have the same atomic number (for example, the atomic number of helium is always 2). It is denoted by the symbol 10 n. In contrast, Isotopes are those elements having the same atomic number and different mass numbers. 2)An isotope of cobalt is used in treatment of cancer. Requested URL: byjus.com/question-answer/what-is-the-reason-for-the-different-atomic-masses-of-the-isotopes-of-an-element/, User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36. They have the same number (and electrons) of protons, but different neutron numbers. Explain. Chapter 1.6: Isotopes and Atomic Masses - Chemistry LibreTexts In the nickel nucleus represented above, the atomic number 28 indicates the nucleus contains 28 protons, and therefore, it must contain 31 neutrons in order to have a mass number of 59. These are called radioisotopes. Since the isotopes of an element have same atomic number, they have same electronic configuration and also similar chemical properties. J. Chadwick discovered a sub-atomic particle which has no charge but has mass nearly equal to that of a proton. (e) Valency For instance, lithium exists as an isotope with 3 neutrons, and as an isotope with 4 neutrons, but it doesn't exist as an isotope with 2 neutrons or as an isotope with 5 neutrons. Atoms of elements that have the same atomic number but a different mass number are called isotopes. An atom is first identified and labeled according to the number of protons in its nucleus. Select the correct answer and click on the Finish buttonCheck your score and answers at the end of the quiz, Visit BYJUS for all Chemistry related queries and study materials, Your Mobile number and Email id will not be published. (4.7.1) mass number ( A) = number of protons + number of neutrons. Thus, isotopes may be defined as : Valency of X = (8 7) = 1 Isotopes of a given element contain different numbers of neutrons, therefore, different isotopes have different mass numbers. State the name of the element. For example, carbon has six protons and is atomic number 6. What were the drawbacks in this model ? (a) (i) Most of the -particles passed through the foil undeflected. Isobars are atoms (nuclides) of different chemical elements which differs in the chemical property but has the same physical property. Question 40. Answer: Isotopes have the same atomic number but different atomic mass numbers (a) Electronic configuration Correct the false statement: (a) An atom as a whole is electrically neutral. The example of two Isotopes and Isobars is iron and nickel. Since the two elements have same mass number hut different atomic numbers, these are related to each other as isobars. Find the number of sub-atomic particles in each of these. Question 1. Isotopes are atoms of different masses of the same element. 4.8: Isotopes- When the Number of Neutrons Varies Three elementary particles which constitute an atom are ; electron (e), proton (p) and neutron (n). (CBSE 2014) (CBSE 2011, 2016) Which statement explains why isotopes have different mass numbers? Answer: = 8). The maximum number of electrons which can be present in a particular energy shell of an atom is given by 2n. Carbon atoms with 7 neutrons have an atomic mass of 13 (6 protons + 7 neutrons = 13). (a) Most of the elements exist in nature. Structure of Atom Class 9 Science Notes and Questions Please note that the difference in the mass numbers of the isotopes is because of the difference in the number of neutrons present. Teachoo gives you a better experience when you're logged in. (iv) Name of element X = Chlorine (Cl). By having different numbers of neutrons in their nuclei they get these different masses. Usually, physical properties are different. The site owner may have set restrictions that prevent you from accessing the site. In other words, its energy remains stationary. Many isotopes occur naturally. The atomic number and mass number of an element are 16 and 32 respectively. Created by Jay. Please login :). The radius of the nucleus of an atom is nearly 10. Write the names of three elementary particles which constitute an atom. (b) He2+ ion (z = 2) has two protons, Isobars: Definition, Difference with Isotopes, Videos and Solved Examples Isotopes are known as the atoms of the same element having the same atomic number i.e same number of protons, but different atomic mass numbers i.e different numbers of neutrons. = 6. Why do isotopes of an element show similar chemical properties? Isotopes differ in the number of neutrons each contains Enough water is added to 50.0 mL of a 0.660 M NaOH solution in order to bring the total volume to 450.0 mL. (CBSE 2015) The element is neon (Ne). The physical properties of an element depend on the mass of the atoms.Due to the presence of different number of neutrons,the masses of all isotopes are different.Therefore,the physical properties are different. (CBSE 2012) Introduction Radioactivity pops up fairly often in the news. They have the same number of protons but a different number of neutrons. Question 29. Also give the reason for your answer : What is the charge and mass of canal rays ? The below table gives a few differences between isotopes and isobars. The numbers 12, 13, and 14 are the isotopes atomic masses. (b) Valency of X =8-6 = 2 Identify the most stable atom from the following. For more content on isotopes and isobars register to BYJUS The Learning App. = 40 the number of protons in all the atoms of a particular element is same, therefore to have different mass numbers, isotopes contain different number of neutrons. In the following table, the mass number and the atomic number of certain elements are given : (a) Atomic number (Z) of helium is 2. When they decay, they release particles that may be harmful. Atomic number, atomic mass, and isotopes - Khan Academy of electrons = Atomic no. This number 35 is this isotope of chlorines mass number. Answer: Most of the elements that are found in nature are a combination of several isotopes. (b) Choose the isotopes from the following nuclei : Learn the concept of an Atomic number here. In India on the occasion of marriages the fireworks class 12 chemistry JEE_Main, The alkaline earth metals Ba Sr Ca and Mg may be arranged class 12 chemistry JEE_Main, Which of the following has the highest electrode potential class 12 chemistry JEE_Main, Which of the following is a true peroxide A rmSrmOrm2 class 12 chemistry JEE_Main, Which element possesses the biggest atomic radii A class 11 chemistry JEE_Main, Phosphine is obtained from the following ore A Calcium class 12 chemistry JEE_Main, Differentiate between the Western and the Eastern class 9 social science CBSE, NEET Repeater 2023 - Aakrosh 1 Year Course, CBSE Previous Year Question Paper for Class 10, CBSE Previous Year Question Paper for Class 12. Answer: 5.8: Isotopes - When the Number of Neutrons Varies is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts. Therefore, Na atom has more electrons (11) than Na+ ion (10). These are nucleus and extra nuclear portion. . Atoms that have an equal number of protons but a different number of neutrons and protons are calledisotopes. Generally, elements which have odd atomic numbers will have one or two stable isotopes whereas elements with even atomic numbers will mostly have 3 or more stable isotopes. Define isotopes. (CBSE 2013) Note that the mass numbers (not the number of neutrons) are given to the side of the name. (ii) As a few alpha particles suffered minor deflections and a very few major deflections, this means that these must have met with some obstructions in their path. same element. 5.8: Isotopes - When the Number of Neutrons Varies Isobars are atoms of Isotopes are atoms that have the same atomic number but with different mass numbers. (a) Why are the chemical properties of the isotopes same ? Question 16. The term was first used by Margaret Todd, a Scottish doctor, and writer while consulting with radiochemist Frederick Soddy. It is also defined as variants of a particular element where these variants will have the same number of protons but differ in the number of neutrons in the atom. Example 4.8. same atomic number but different mass number. Teachoo answers all your questions if you are a Black user! (it) 8p + 9n If you have any doubts, please comment below. of protons = Atomic no. Answer: Answer verified by Toppr Upvote (0) Was this answer helpful? Answer Isotopes of an element differ in the number of neutrons in the nuclei so they have a different mass number as the mass number is the sum of a number of protons and neutrons in the nucleus. Answer: When we look at carbon it also has three isotopes namely Carbon-12, Carbon-13, and Carbon-14. These atoms are the isotope named tritium. Weve got your back. Valency of the element = (8 6) = 2 If these are completely filled, this means that : Question 3. A certain particle X has 17 protons, 17 electrons and 18 neutrons //Isotopic Mass - Introduction, Definition, Uses, and FAQs - Vedantu For example, carbon atoms with the usual 6 neutrons have a mass number of 12 (6 protons + 6 neutrons = 12), so they are called carbon-12. Question 8. Different isotopes of elements are used in fields like carbon dating, nuclear reactors and in medicinal purposes. It has 6 protons and 8 neutrons. It therefore, does not take part in chemical combination and its valency is zero. You can relate the concepts of isotopes with this example. These are called isotopes. \[\text{number of neutrons} = 65 - 30 = 35\]. If we talk about the element Hydrogen, it has three stable isotopes namely protium, deuterium, and tritium. O isotopes differ in the number of protons and electrons each contains O Isotopes differ in the number of protons . Determine the number of protons, electrons, and neutrons of an element with a given mass number. Learn Insta try to provide online science tutoring for you. How many protons, electrons, and neutrons are in an atom of zinc-65? Number of protons and electrons in isobars is different . The atomic mass can be expressed using unified atomic mass units (u). Find : State whether the following statements are true or false. Protons were discovered by Goldstein. Why do isotopes have the same atomic number but different mass numbers? Question 7. (CBSE 2015) (c) What are the number of protons, neutrons and electrons in 5927Co and 10847Ag ? However, their atomic numbers are the same. State the postulates stated by Neils Bohr in order to overcome the objection as raised against Rutherfords model of atom. Dalton always experimented with large chunks of an element - chunks that contained all of the naturally occurring isotopes of that element. Why Isotopes have different Physical Properties? - GeeksforGeeks It turns out that elements found in nature exist as constant uniform mixtures of their naturally occurring isotopes. Hope given Previous Year Question Papers for CBSE Class 9 Science Chapter 4 Structure of the Atom are helpful to complete your science homework. (i) nuclear reactor, Contact Us. Show the electron distribution in magnesium atom and magnesium ion diagrammatically and also give their atomic numbers. (a) Canal rays are the rays which originate in the discharge tube experiment and move away from the anode. is different (CBSE 2012) Elements having same mass number but different atomic number. The elements which have same no. . (CBSE 2014) Can you explain this answer? (a) Select the pair of isobars from the above table. (Python), Class 12 Computer Science (c) Which two sub-atomic particles are equal in number in a neutral atom ? For example, All three of them have the same number of protons, but the numbers of neutrons differ. For example, carbon-12 is an isotope of carbon with a mass number of 12. Atomic mass is the sum of some protons and the number of neutrons and atomic number is equal to the number of protons. Q. In nature, only certain isotopes exist. (f) Name (CBSE 2011) This process is called radioactive decay. (ii) carbon. Isotopes are variations of an element that have the same number of protons but different numbers of neutrons. There may be different types of atoms of a chemical element. It is directed away from the nucleus. Answer: It is located in the nucleus of an atom along with proton. (CBSE 2015) Every chemical element has one or more isotopes. State whether the given statement is true or false : Right on! (i) hydrogen, In this, 286 are said to be primordial nuclides which are believed to have existed since the formation of the Solar System. 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