Class-9 » Science. Which of the following correctly represents the electronic distribution in the Mg atom? Capacity is 8 ) No. Page No 55: Question 12: If Z = 3, what would be the valency of the element? Periodic classification class 10 Questions from: Summative Assessment – II In 1789, Lavoisier first attempted to classify the elements into two divisions namely Metals and Non-metals. Lewis dot structures reflect the electronic structures of the elements, including how the electrons are paired. Capacityis 8 ) 1st orbit has only 1s orbital. How to Determine Electron Configuration . Rather than writing: ... Chromium is element No. Its electronic configuration is 2, 1. Electron Configuration Notation:-shows the arrangment of electrons around the nucleus of an atom. A sublevel is filled or half-filled before the next sublevel is entered. In this way, you would consider the electronic configuration of oxygen to be $1s^22s^22p^4$. This consists of 1 mark Questions, 3 Mark Numericals Questions, 5 Marks Numerical Questions and previous year questions from Periodic Classification of Elements Chapter. An electron configuration can quickly and simply tell a reader how many electron orbitals an atom has as well as the number of electrons populating each of its orbitals. Another important point to note, is that the filling of electrons in subshells doenst actually fill from low to high. The next element, sodium would be the same with one additional electron in the 3s orbital. So we could also write the electron configuration for helium right, as one s two. This has a high melting point (800 ºC) and dissolves in water to to give a conducting solution. Structure of the Atom. 10 ; View Full Answer And valency of the following: chlorine. 4. Electronic configuration of Na is: 2, 8, 1 Since, K can have Maximum of 2 electrons using 2 2 we can say that, it is filled completely. Aufbau Principle • Electrons occupy orbitals of lower energy first. Share 0. writw the electronic configuration of sodium ion and chloride ion.comment aboout their chemical reactivity in comparison to the respective neutral atoms. Structure of the Atom Class 9 MCQs Questions with Answers. of electron in 2nf orbit = 8 ( Max. And once again what that means, is we're talking about an s orbital, s orbital in the first energy level, and there are two electrons in that s orbital. Electron Configuration • The way in which electrons are distributed among the various orbitals of an atom 8. the Lewis dot structure of sodium: B: electronic configuration of boron =122221 There are 3 valence electrons in Boron atom. 0 ; chlorine atomic number is 17 so EC-2.8.7 valency-must be 1 or 7. When sodium is burned in a chlorine atmosphere, it produces the compound sodium chloride. Capacity is 2 ) No. “Bohr atomic model” forms the basis of the electronic structure of an atom. So we can say that the valence electron of Na is 1. L can have maximum of 8 electrons, so, we can say it is filled completely. Sodium has one electron in its outermost shell. So the electron configuration of calcium (Ca) which has 20 electrons, can be written as: [Ar]4s². of electron in 3rd orbit = 16-(2+8) = 6 ( Max. There is a special rule called aufbau principle (german word for 'building up'). Note that when writing the electron configuration for an atom like Cu, the 3d is usually written before the 4s. Distribution of Electrons in Different Orbits. Hence, the valency of the element is 1 (since the outermost shell has only one electron). When their electron configurations are added to the table (Figure 6.29), we also see a periodic recurrence of similar electron configurations in the outer shells of these elements. Cl - = 2,8 An Ionic bond is formed between sodium ion and chloride ion by complete transfer of electron from sodium to chlorine. Copper is element No. 7 ; atomic no. Also, na me the element. Diagrams have been used wherever necessary to be able to learn visually. The relation between orbital filling and the periodic table 10. Whereas Cl has seven electrons in its outermost shell. An element has electronic configuration 2, 6; the element is (a) Carbon (b) Nitrogen (c) Oxygen (d) Fluorine. Lewis dot structures are commonly referred to as electron dot structures or Lewis structures. Predict the nature of bonding in the compound formed. Use the element blocks of the periodic table to find the highest electron orbital. Important Question for Class 10 Science Periodic Classification of Elements PDF will help you in scoring more marks.. To arrive at the electron configurations of atoms, you must know the order in which the different sublevels are filled. The electron configuration for silver (Ag) is based upon the place meant of silver in the fifth row of the periodic table in the 11th column of the periodic table or the 9th column of the transition metal or d block. 9. Periodic Classification of Elements Chapter Wise Important Questions Class 10 Science SHORT ANSWER […] If your periodic table doesn’t agree with this, your answers for elements near the f-orbitals may be slightly different. Key Features of NCERT Solutions for Class 9 Science Chapter 4 – Structure of The Atom. b. For example, the atomic number of sodium is 11. Class-9 » Science. write the electronic configuration of chlorine sodium, silicon. Write the electronic configuration and valency of the following: (i) Chlorine (ii) Sodium and (iii) Silicon In order to achieve the nearest noble gas configuration, it gains one electron to form Chloride ion. Calculations and electronic configurations have been explained in detail while solving. When both sodium and chlorine combine and share their electron and have eight electrons in their outermost shell then it is said that the compound formed follows the octet rule. So we can say the Valence electron for Cl is 7. The relation between orbital filling and … of electron in 1st orbit = 2 ( Max. He was the person to describe the arrangement of electrons (electronic configuration) in different orbits/shells. Electron Configuration Notation:-shows the arrangment of electrons around the nucleus of an atom. The electron configuration can be seen as consisting of the core electrons, which is equal to the configuration of the most recent noble gas, plus the valence (outer electron) configuration of the element. The electronic configuration of an atom can be predicted from its atomic number. Electron configurations describe where electrons are located around the nucleus of an atom. Electron orbitals are differently-shaped regions around an atom's nucleus where electrons are mathematically likely to be located. Actual experimental data shows the value to be [Ar]3d 5 s 1. Class –XI–CBSE ... electronic configuration of sodium 1 2222631 There is only one valence electron in an atom of sodium. Electron Configurations - Solutions Note: The electron configurations in this worksheet assume that lanthanum (La) is the first element in the 4f block and that actinium (Ac) is the first element in the 5f block. Gist of Lesson for Quick Revision (By JSUNIL) Question: If an element A is a member of group 14, write the formulae of its chloride and oxide. Neils Bohr gave the planetary model of an atom. An atom's electron configuration is a numeric representation of its electron orbitals. Sodium chloride is an ionic compound, and the crystalline solid has the structure shown on the right. He was the first person to suggest the periodicity in the properties of the elements. Number of Sulphur = 16 No. Electrons enter available sublevels in order of their increasing energy. At. Share 4. The radioactive isotope used in the treatment of cancer is: (a) plutonium-239 (b) arsenic-74 (c) cobalt-60 (d) iodine-131. The electron configuration states where electrons are likely to be in an atom. If you don’t have a chart, you can still find the electron configuration. Sodium (Na) Magnesium (Mg) Aluminum (Al) Silicon (Si) Phosphorus (P) Sulfur (S) Chlorine (Cl) Argon (Ar) Potassium (K) Calcium (Ca) Chromium (Cr, Cr 2+, Cr 3+) Copper (Cu, Cu +, Cu 2+) Iron (Fe, Fe 2+, Fe 3+) Read my article in Science Education based on my dissertation. NCERT Solution for Class 9 science - structure of the atom 55 , Question 11. NCERT Solutions , Class 9, Chemistry . 4.6 Electronic configuration (ESABE) The energy of electrons (ESABF). Because they are in the outer shells of an atom, valence electrons play the most important role in chemical reactions. Ans. Share with your friends. According to J.J. Thomson’s model of an atom, the electrons are embedded all over in the positively charged spheres. Answer: By Z = 3, we mean that the atomic number of the element is 3. Share with your friends. How to Find Electron Configuration. When their electron configurations are added to the table (Figure 1.5.6), we also see a periodic recurrence of similar electron configurations in the outer shells of these elements. 3 ; the valency of chlorine is 1 . Na atom contains 11 electrons. 24, and according to the Aufbau principle, the electron configuration should be [Ar]3d4s2. Question 1. (i) Write the electron-dot structures for sodium (11), Oxygen (8), chlorine (17) and magnesium (12). You can refer to NCERT Solutions for Class 9 Science Chapter 4 Structure of the Atom to revise the concepts in the syllabus effectively and improve your chances of securing high marks in your board exams. For example, the electron configuration of lithium, 1s²2s¹, tells us that lithium has two electrons in the 1s subshell and one electron in the 2s subshell. Actual configurations have not been verified. So one s two is the electron configuration for helium. sodium, silicon. Electronic configuration is : Cl = 2, 8, 7 So it contains 7 valence electron. Lewis Dot Structure. 3. And since we have two electrons in the one s orbital, we can't fit in any more electrons. Q3. Because they are in the outer shells of an atom, valence electrons play the most important role in chemical reactions. Sodium atoms have 11 For example, the atomic number of sodium is 11. NCERT solutions enable students to prepare for CBSE Class 9 examination stress-free. Chlorine - 2,8,7 Sodium - 2,8,1 Silicon - 2,8,6. Show the formation of Na 2 O and MgO by the transfer of … Structure of the Atom. 2. Lewis defined a base as an electron pair donor and an acid as an electron pair acceptor. 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