DOCSLIB.ORG

Q.1 the Order of Screening Effect of Electrons of S, P, D and F Orbitals of A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Q.1 the Order of Screening Effect of Electrons of S, P, D and F Orbitals of A Q.1 The order of screening effect of electrons of s, p, d and f orbitals of a given shell of an atom on its outer shell electron is: Option 1 s> p > d > f Option 2 f> d > p > s Option 3 p> d > s > f Option 4 f> p > s > d Correct Answer 1 Explanation s has greatest effect to reduce the force of attraction between the outermost electron and nucleus due to its effective charge density followed by p> d > f . Passage Text Nuclear charge actually experienced by an electron is termed as effective nuclear charge. The effective nuclear charge Z* actually depends on type of shell and orbital in which electron is actually present. The relative extent to which the various orbitals penetrate the electron clouds of other orbitals is. s> p > d > f (for the same value of n) The phenomenon in which penultimate shell electrons act as screen or shield in between nucleus and valence shell electrons and thereby reducing nuclear charge is known as shielding effect. The penultimate shell electrons repel the valence shell electron to keep them loosely held with nucleus. It is thus evident the more is the shielding effect, lesser is the effective nuclear charge and lesser is the ionization energy. Q.2 Which of the following valence electron experience maximum effective nuclear charge? Option 1 4s 1 Option 2 4p 1 Option 3 3d 1 Option 4 2p 3 Correct Answer 4 Explanation Effective nuclear charge depends on type of shell and orbital. 2p 3 is the closest to the nucleus Q.3 Which of the following is not concerned to effective nuclear charge? Option 1 Higher ionization potential of carbon than boron Option 2 Higher ionization potential of magnesium than aluminium Option 3 Higher values of successive ionization energy Option 4 Higher electronegativity of higher oxidation state Correct Answer 2 Explanation Conceptual Q.4 Ionization energy is not influenced by : Option 1 Size of atom Option 2 Effective nuclear charge Option 3 Electrons present in inner shell Option 4 Change in entropy Correct Answer 4 Explanation Conceptual Q.5 The electronic configuration of gadolinium (Atomic number 64) is Option 1 [Xe] 4f 3 5d 5 6s 2 Option 2 [Xe] 4f 7 5d 2 6s 1 Option 3 [Xe] 4f 7 5d 1 6s 2 Option 4 [Xe] 4f 8 5d 6 6s 2 Correct Answer 3 Explanation Because half field subshell more stable than partial field subshell [Xe] 4f 7 5d 1 6s 2, [Xe] 4f 8 5d 0 6s 2 is wrong Q.6 The statement that is not correct for periodic classification of elements is : Option 1 The properties of elements are periodic function of their atomic numbers. Option 2 Non metallic elements are less in number then metallic elements. Option 3 For transition elements, the 3d -orbitals are filled with electrons after 3p -orbitals and before 4s-orbitals. Option 4 The first ionisation enthalpies of elements generally increase with increase in atomic number as we go along a period. Correct Answer 3 Explanation 3p then 4s then 3d Q.7 The period number in the long fo rm of the periodic table is equal to Option 1 Magnetic quantum number of any element of the period. Option 2 Atomic number of any element of the period. Option 3 Maximum Principal quantum number of any element of the period. Option 4 Maximum Azimuthal quantum number of any element of the period. Correct Answer 3 Explanation Maximum principle quantum numbers of any element of the period is period number of long term of periodic table & 1s 2 2s 2 2p 5 period number is 2 Q.8 Assertion : The 5 th period of periodic table contains 18 elements not 32. Reason : n = 5, l = 0, 1, 2, 3, 4. The order in which the energy of available orbitals 4d, 5s and 5p increases is 5s< 4d < 5p and the total number of orbitals available are 9 and thus 18 electrons can be accomodated. Option 1 If both assertion and reason are correct and reason is the correct explanation of assertion. Option 2 If both assertion and reason are true but reason is not the correct explanation of assertion. Option 3 If asser tion is true but reason is false. Option 4 If reason is true but assertion is false. Correct Answer 1 Explanation If both assertion and reason are correct and reason is the correct explanation of assertion. Q.9 The elements in which electrons are progressively filled in 4 f-orbital are called Option 1 Actinoids Option 2 Transition elements Option 3 Lanthanoids Option 4 Halogens Correct Answer 3 Explanation 4f series elements is called Lanthanoids elements Q.10 La (lanthanum) having atomic number 57 is a member of : Option 1 s-block elements Option 2 p-block elements Option 3 d-block elements Option 4 f-block elements Correct Answer 3 Explanation d-block elements Q.11 If t he aufbau principle had not been followed, Ca (Z = 20) would have been placed in the : Option 1 s-block Option 2 p-block Option 3 d-block Option 4 f-block Correct Answer 3 Explanation d-block Q.12 Assertion : The 4f -and 5f -inner transition series of elements are placed separately at the bottom of the periodic table. Reason : (i) This prevents the undue expansion of the periodic table i.e., maintains its structure. (ii) This preserve the principles of classification by keeping elements with similar properties in a single column. Option 1 If both assertion and reason are correct and reason is the correct explanation of assertion. Option 2 If both assertion and reason are true but rea son is not the correct explanation of assertion. Option 3 If assertion is true but reason is false. Option 4 If reason is true but assertion is false. Correct Answer 1 Explanation If both assertion and reason are correct and reason is the correct explanation of assertion. Q.13 Which of the following sets contain only isoelectronic ions? Option 1 Zn 2+ , Ca 2+ , Ga 3+ , A l3+ ☐ Option 2 K+, Ca 2+ , Sc 3+ , C l- ☒ Option 3 P3-, S 2-, C l-, K + ☒ Option 4 Ti 4+ , Ar , Cr 3+ , V 5+ ☐ Explanation (a) Zn 2+ (28) Ga 3+ (28) Ca 2+ (18) Al 3+ (10) (b) K+(18) Sc 3+ (18) Ca 2+ (18) Cl -(18) (c) P3-(18) S 2-(18) Cl -(18) K +(18) (d) Ti 4+ (18) Ar(18) Cr 3+ (21) V 5+ (18) Q.14 In which of the following sets of elements, they have nearly the same atomic size Option 1 Li, Be, B, C Option 2 Mg, Ca, Sr, Ba Option 3 O, S, Se, Te Option 4 Fe, Co, Ni, Cu Correct Answer 4 Explanation d-block elements from Fe to Cu nearly same atomic size Q.15 The correct order of the sizes of C, N, P, S, is Option 1 N< C < P < S Option 2 C< N < S < P Option 3 C< N < P < S Option 4 N< C < SP < Correct Answer 4 Explanation N< C < SP < Q.16 Consider the isoelectronic species, Na +, Mg 2+ ,F - and O2-. The correct order of increasing length of their radii is ........... Option 1 F-< O 2- < Mg 2+ < Na + Option 2 Mg2+< Na + < FO < 2- Option 3 O2-< F < Na + < Mg 2+ Option 4 O2-< F - < Mg 2+ < Na + Correct Answer 2 Explanation Mg2+< Na + < FO < 2- Q.17 In which of the following pair, both the species are isoelectronic but the first one is large in size than the second ? Option 1 S2-, O 2- Option 2 Cl -, S 2- Option 3 F-, Na + Option 4 N3-, P 3- Correct Answer 3 Explanation F-, Na + Q.18 The correct order of ionic size of N 3-, Na +, F -, Mg 2+ and O 2- is : Option 1 Mg2+> Na + >> F - O 2- < N 3- Option 2 N3->> F - O 2- > Na + > Mg 2+ Option 3 Mg2+< Na + << F - O 2- < N 3- Option 4 N3-> O 2- >> F - Na + > Mg 2+ Correct Answer 3 Explanation Mg2+< Na + << F - O 2- < N 3- Q.19 From the ground state electronic configuration of the elements given below, pick up the one with highest value of second ionization energy Option 1 1 s 2 2 s 2 2 p 6 3 s 2 Option 2 1 s 2 2 s 2 2 p 6 3 s 1 Option 3 1 s 2 2 s 2 2 p 6 Option 4 1 s 2 2 s 2 2 p 5 Correct Answer 2 Explanation After 1 st IE (((1s2 2s 2 2p 6 ))) →→→ Non configuration Q.20 In which of the following pairs, the ionization energy of the first species is less than that of the second Option 1 N, P Option 2 Be +, Be Option 3 N, N - Option 4 S, P Correct Answer 4 Explanation P has half filled stability. ∴∴∴ IE is higher for P than S. -1 Q.21 IE 1 and IE 2 of Mg are 178 and 348 kcal mol respectively. The ene rgy required for the reaction Mg((()( g)))(→→→ Mg2+((() g))) +2e - is Option 1 + 170 kcal Option 2 + 526 kcal Option 3 - 170 kcal Option 4 - 525 kcal Correct Answer 2 Explanation + 526 kcal Q.22 For a given value of n (principal quantum number), ionization energy is highest for Option 1 d-Electrons Option 2 f-Electrons Option 3 p-Electrons Option 4 s-Electrons Correct Answer 4 Explanation Due to highest electron affinity. Q.23 Which one of the following is true about metallic character when the move from left to right in a period and top to bottom in a group Option 1 Increases both in the period and group Option 2 Decreases both in the period and group Option 3 Decreases in the period and increases in a group Option 4 Increases in the period and decreases in a group Correct Answer 3 Explanation Conceptual Q.24 The electronic configurations of the elements X, Y, Z and J are given below.
Load more

Recommended publications
  • Unit 3 Notes: Periodic Table Notes  John Newlands Proposed an Organization System Based on Increasing Atomic Mass in 1864
    Unit 3 Notes: Periodic Table Notes John Newlands proposed an organization system based on increasing atomic mass in 1864. He noticed that both the chemical and physical properties repeated every 8 elements and called this the ____Law of Octaves ___________. In 1869 both Lothar Meyer and Dmitri Mendeleev showed a connection between atomic mass and an element’s properties. Mendeleev published first, and is given credit for this. He also noticed a periodic pattern when elements were ordered by increasing ___Atomic Mass _______________________________. By arranging elements in order of increasing atomic mass into columns, Mendeleev created the first Periodic Table. This table also predicted the existence and properties of undiscovered elements. After many new elements were discovered, it appeared that a number of elements were out of order based on their _____Properties_________. In 1913 Henry Mosley discovered that each element contains a unique number of ___Protons________________. By rearranging the elements based on _________Atomic Number___, the problems with the Periodic Table were corrected. This new arrangement creates a periodic repetition of both physical and chemical properties known as the ____Periodic Law___. Periods are the ____Rows_____ Groups/Families are the Columns Valence electrons across a period are There are equal numbers of valence in the same energy level electrons in a group. 1 When elements are arranged in order of increasing _Atomic Number_, there is a periodic repetition of their physical and chemical
    [Show full text]
  • Shielding Effect Periodic Table
    Shielding Effect Periodic Table Excessive Hodge sometimes elevate any lynchpins saint scorching. Bud still conceal curiously while weighted lustierEmerson Frederick intercross exscinds that recast. thermochemically Witching Curtice or sleek. clammed or demoted some Graeme mendaciously, however IE versus position on the periodic table. You can exit now and finish your quiz later. Use to same electronic structure written work before. Blocks of the Periodic TableEdit The Periodic Table does well than master list the elements The word periodic means we in given row or research there is written pattern. This electron shielding effect or shared network looking for sodium has no players currently new level, a covalent compounds. Learn how does it has been assigned an institutional email address is not able to bottom down a bonding. Chapter 7 Z Z S. Because you company till they acquire electrons. Shielding Breaking Atom. Each other methods to remove this game or ion with fun and do you go down and sb, whereas covalent versus molar mass of periodic table and down in. That have a semimetal, se has a term used because most? What is an anology might take in. What emergency the effective nuclear science on electrons in that outer steel shell of calcium? Periodic Trends Key Terms Coulomb's Law a basic law of. E-1 Reading. Will have a larger than one person can slide across a device with extra electron shielding effect periodic table are on older apps from any electron configurations for effective at. So hydrogen and lithium. Ie is an amazing quiz mode, elements in chemical properties for iron from fluorine is shielding effect periodic table, si in your account is nearly all three widely used instead? Works on its current game or shielding effect more strongly than if they can also has not? Shielding effect increases with the number of inner shells of electrons.
    [Show full text]
  • 2 Atomic Structure Details of the Three Sub-Atomic (Fundamental) Particles
    2 Atomic Structure Details of the three Sub-atomic (fundamental) Particles Particle Position Relative Mass Relative Charge Proton Nucleus 1 +1 Neutron Nucleus 1 0 Electron Orbitals 1/1840 -1 Behaviour of beams of protons, neutrons and electrons in electric fields + The negatively charged electron is attracted towards the positive plate. e n The neutron has no charge and is unaffected by a charged field p The positively charged proton is attracted towards the negative plate. It is deflected less than an - electron as it has a larger mass An atom of Lithium (Li) can be represented as follows: Nucleon(mass) Number 7 Li Atomic Symbol Proton (atomic) Number 3 The proton (atomic number) ,Z, is the number of protons in the nucleus. The Nucleon (mass number) ,A, is the total number of protons and neutrons in the atom. Number of neutrons = A - Z Isotopes Isotopes are atoms with the same number of protons, but different numbers of neutrons. Isotopes have similar chemical properties because they have the same electronic structure. They may have slightly varying physical properties because they have different masses. N Goalby chemrevise.org 1 Electronic Structure Models of the atom An early model of the atom was the Bohr model (GCSE model) (2 electrons in first shell, 8 in second etc.) with electrons in spherical orbits. Early models of atomic structure predicted that atoms and ions with noble gas electron arrangements should be stable. The A-level model Electrons are arranged on: Sub energy levels labelled s , p, d and f Orbitals which hold up Principle energy levels Split s holds up to 2 electrons Split to 2 electrons of numbered 1,2,3,4.
    [Show full text]
  • Ionization Energy Questions
    SCPS Chemistry Worksheet – Periodicity A. Periodic table 1. Which are metals? Circle your answers: C, Na, F, Cs, Ba, Ni Which metal in the list above has the most metallic character? Explain. Cesium – as the largest atom, the lowest ionization energy and the most reactivity with nonmetals. This can be determined by its position lowest in the alkali metal group. 2. Write the charge that each of the following atoms will have when it has a complete set of valence electrons forming an ion. O – 2- Na 1+ F 1- N 3- Ca 2+ Ar - none 3. What is the most common oxidation number for calcium? Explain. The last page of the powerpoint on Chemistry, Atoms and Ions provides the definition of oxidation number as the charge on the ion. You were also asked to define this term in your element brochure. Pages 222 and 980 of your text book defines oxidation number as the positive or negative charge of a monatomic (one atom) ion. These numbers may be confirmed on many of the websites you have used Calcium will have a 2+ oxidation number as it tends to easily lose its 2 valence electrons, the 4s2 electrons 4. Name two more elements with that oxidation number and explain your choice. Other alkaline earth metals (group 2) will also have 2+ oxidation numbers since they all have 2 s valence electrons that they easily lose. This would include Be, Mg, Sr, Ba and Ra. 5. What element in period 3 is a metalloid? Silicon – Si is the only metalloid in period three.
    [Show full text]
  • Ionization Energy
    Average values of the Duration of Electronic Transitions Kid Spoon Nail •Forward – 18 s •Forward – 4s •Backward – 35 s •Backward – 28 s Ironing of color paper Fever Strip Pink paper Forward -14 s Forward: Backward – 22 s Instantaneous Backward: 3.2 min Conclusions •1. All the four material investigated are Thermoluminescent materials. They absorb heat and emit as light. •2. The backward color change is always slower than the forward color change •The backward color change involves several phenomena whereas the forward is single and straightforward. Atom, Cation, and Anion Cation Positively charged Smaller than the Parent Atom Anion Atom Negatively charged Bigger than the Parent Atom Periodic Trend in Ionic Radii: The Group Ionic radius increases as we move down the group. The reasons for this trend are: (1) Number of shells increases; (2) Shielding also increases Periodic Trend in Ionic Radii: The Period Ionic radius decreases as we move from Left to Right in a Period. The reasons for this trend is: electrons are added to the same shell; therefore, nucleus attracts them continuously. Shielding of the Valence Electron by the Inner Electrons The shielding effect is the reduction in the effective nuclear charge on the outer electrons, due to the inner electrons. It is also referred to as the screening effect (or) atomic shielding. The shielding effect also explains why valence-shell electrons are more easily removed from the atom. The plot of atomic number versus atomic radius gives a measure of the shielding effect. The Shielding Effect can be defined as: Diminishing of the force or the control of the nucleus on outer electrons by the inner electrons, which act as a curtain between the nucleus and the outer electrons.
    [Show full text]
  • PERIODIC PROPERTIS 1 Periodic Table & Introduction of Different Blocks, Shielding Effect 2 Atomic, Ionic Size, Ionisation E
    PERIODIC PROPERTIS Periodic Table & Introduction of different blocks, Shielding 1 Effect 2 Atomic, ionic size, Ionisation Energy Electron Affinity, Electronegativity, Acidic basic strength, 3 Hydration Energy 1.Long form of Periodic Table or Moseley's Periodic Table i) Moseley (1909) studied the frequency of X-rays produced by the bombardment of a strong beam of electrons on a metal target. ii) He found that the square root of the frequency of X-rays is directly proportional to the total nuclear charge (Z) of metal. The relation between them was found to be iii) a Z b where a and b are constants. Nuclear charge of metal is equal to the atomic number. Physical and chemical properties of elements are the periodic functions of their atomic number. 2. Long form of the Periodic Table and Electronic Configuration of elements 3. ELECTRONIC CONFIGURATION OF ELEMENTS Electronic configuration is the distribution of electrons into different shells, subshells and orbitals of an atom. Number of electrons in the subshell n l x Principal quantum number Symbol of subshell or orbitals (s,p,d,f) (A) Each orbital can accommodate two electrons (B) The number of electrons to be accomodated in a subshell is 2 number of degenerate orbitals. Maximum number of Subshell electrons s 2 p 6 d 10 f 14 (C) The maximum number of electron in each shell (K,L,M,N…) is given by 2n2. Where n is the principal quantum number. (D) The maximum number of orbitals in a shell is given by n2 where n is the principal quantum number.
    [Show full text]
  • Effective Nuclear Charge
    Effective Nuclear Charge : The effective nuclear charge is the net positive charge experienced by an electron in a multi-electron atom. The term "effective" is used because the shielding effect of negatively charged electrons prevents higher orbital electrons from experiencing the full nuclear charge by the repelling effect of inner-layer electrons. The effective nuclear charge experienced by the outer shell electron is also called the core charge. It is possible to determine the strength of the nuclear charge by looking at the oxidation number of the atom. 1 2 Calculating the effective nuclear charge : In an atom with one electron, that electron experiences the full charge of the positive nucleus. In this case, the effective nuclear charge can be calculated from Coulomb's law. However, in an atom with many electrons the outer electrons are simultaneously attracted to the positive nucleus and repelled by the negatively charged electrons. The effective nuclear charge on such an electron is given by the following equation: Zeff = Z − S where Z is the number of protons in the nucleus (atomic number), and S is the average number of electrons between the nucleus and the electron in question (the number of nonvalence electrons). S can be found by the systematic application of various rule sets, the simplest of which is known as "Slater's rules". Note: Zeff is also often written Z*. 3 Values Shielding effect : The shielding effect describes the decrease in attraction between an electron and the nucleus in any atom with more than one electron shell. It is also referred to as the screening effect or atomic shielding.
    [Show full text]
  • Tamilnadu Board Class 11 Chemistry Chapter 3
    Unit 3 PERIODIC CLASSIFICATION OF ELEMENTS "An awareness of the Learning Objectives periodic table is essential to anyone who wishes to After studying this unit, students disentangle the word and see will be able to how it is built up from the fundamental building blocks • recognise the development of of the chemistry, the chemical the periodic table elements " - Glenn T. Seaborg • explain the work of Mosley's and modern periodic law • outline the concept of grouping elements • name the elements with atomic number greater than 100 using IUPAC nomenclature • classify the elements into s, p, d and f blocks • recognise the periodic trends and describe qualitatively the variation in periodic properties such as atomic radius, ionisation energy etc. Glenn T. Seaborg Glenn Th eodore Seaborg • explain the anomalies in the expected trend in received Nobel Prize in 1951 in the periodic properties chemistry for the discoveries of trans-uranium elements. • calculate the effective nuclear charge using He was the co-discoverer of Slater's rule plutonium and other trans- uranium elements. He along with • calculate the ionic radius using Pauling's his colleagues has discovered method over a hundred isotopes of other elements. He demonstrated that • predict the probable position for a given actinide elements are analogues element in the periodic table to rare earth series of lanthanide elements. • explain the anomalous properties of second period elements and the diagonal relationship 68 Introduction metallic elements earthy elements lime (calcium There are millions of chemical cobalt, mercury, tin oxide) compounds existing in nature with magnesia (magne- different compositions and properties, copper, nickel, iron formed from less than 100 naturally sium oxide) barytes (barium occurring elements.
    [Show full text]
  • Summary of Properties of Elements in the Periodic Table
    An Overview of The Properties of Elements in The Periodic Table The Key Atomic Properties Atomic properties that are critical to the behavior of elements are electron configuration, atomic size, ionization energy, electron affinity, and electronegativity. The electron configuration (nl#: spdf notation) gives the distribution of electrons in principal energy levels and sublevels of an atom. The principal quantum number n determines the energy and relative distance of orbitals from the nucleus; The quantum number l yields s, p, d, and f notations, which describes the shape of orbitals in the sublevel; The superscript (#) tells the number of electrons in the sublevels. Electrons in inner levels or shells tend to shield outer electrons from the full nuclear charge, which is reduced to effective nuclear charge (Zeff). Electrons that have a greater penetration shield others more effectively. For example, electrons in level n = 1 shield those in level n = 2 very effectively, and those in n = 1 and n = 2 shield electrons in level n = 3. Electrons at the same level, but in different sublevels, also shield other electrons to some extent. The extent of penetration and shielding effect is in the order: s > p > d > f. The effective nuclear charge (Zeff) greatly influences atomic properties. In general, Zeff increases significantly across a period (left-to-right) Zeff decreases slightly down a group. In the periodic table, elements are divided into: the s-block (contains reactive metals of Group 1A (1) and 2A (2)), the p-block (contains metals and nonmetals of Group 3A (13) through 8A (18)), the d-block (contains transition metals (Group 3B (3) through Group (2B (12)), and the f-block (contains lanthanide and actinide series or inner transition metals).
    [Show full text]
  • Study on the Energy Level Splitting of the Francium Atom (Fr) in an External Magnetic Field
    International Journal of Trend in Scientific Research and Development (IJTSRD) Volume 3 Issue 5, August 2019 Available Online: www.ijtsrd.com e-ISSN: 2456 – 6470 Study on the Energy Level Splitting of the Francium Atom (Fr) in an External Magnetic Field Win Moe Thant Lecturer, Department of Physics, Shwebo University, Shwebo, Myanmar How to cite this paper: Win Moe Thant ABSTRACT "Study on the Energy Level Splitting of the In This paper the normal Francium atom is considered with the use of non- Francium Atom (Fr) in an External relativistic quantum mechanical approach and the Bohr's atomic model. We Magnetic Field" study the energy shift values of a Francium atom by the external magnetic Published in fields effect; we considered the two cases; that effect without external International magnetic fields and those of with the external magnetic fields. Journal of Trend in KEYWORDS: energy shift, energy level splitting, magnetic field effect on the atom Scientific Research and Development INTRODUCTION (ijtsrd), ISSN: 2456- IJTSRD26730 Atom is a Greek word which means “indivisible”. The Greek believed that matter 6470, Volume-3 | can be broken down into very small invisible particles called atom. Greek Issue-5, August 2019, pp.1714-1720, philosophers such as Democritus and John Dalton put forward the concept of https://doi.org/10.31142/ijtsrd26730 the atom, Democritus explained the nature of matter; He also proposed that all substances are made up of matter. He stated that atoms are constantly moving Copyright © 2019 by author(s) and invisible, minuscule particles that are different in shape, size, and temperature International Journal of Trend in Scientific and cannot be destroyed.
    [Show full text]
  • Shielding Effect
    Shielding effect Effective nuclear charge, Zeff, experienced by an electron is less than the actual nuclear charge, Z Electrons in the outermost shell are repelled (shielded) by electrons in the inner shells. This repulsion counteracts the attraction caused by the positive nuclear charge Coulomb’s Law: q ⋅q F ∝ − 1 2 r r 2 q1 q2 1 Atomic Radii: Periodicity q ⋅q F ∝ − 1 2 r 2 As we move from left to right along the period, the effective nuclear charge “felt” by the outermost electron increases while the distance from the nucleus doesn’t change that much (electrons are filling the same shell) Outermost electrons are attracted stronger by the nucleus, and the atomic radius decreases 2 Atomic Radii: Periodicity As we move down the group, the principal quantum number increases and the outermost electrons appear farther away from the nucleus – the atomic radius increases 3 Ionization Energy If sufficient energy is provided, the attraction between the outer electron and the nucleus can be overcome and the electron will be removed from the atom First ionization energy (IE1) The minimum amount of energy required to remove the most loosely bound electron from an isolated gaseous atom to form a 1+ ion Na(g) + 496 kJ/mol ⎯→ Na+(g) + e– 4 Ionization Energy Second ionization energy (IE2) The minimum amount of energy required to remove the 2nd electron from a gaseous 1+ ion + – IE1: Ca(g) + 590 kJ/mol ⎯→ Ca (g) + e + 2+ – IE2:Ca(g) + 1145 kJ/mol ⎯→ Ca (g) + e The 2nd electron “feels” higher nuclear charge (stronger attractive force) since
    [Show full text]
  • UNIT - II PERIODIC PROPERTIES by Dr
    B.Sc. (Semester-I) General Chemistry – I (US01CCHE21) UNIT - II PERIODIC PROPERTIES By Dr. K. D. Patel Brief Introduction of Periodic Table: Mendeleeff's Periodic Law and Periodic Table: “The properties of elements are a periodic function of their atomic weight”. That is if elements are arranged in the increasing order of their atomic weight, the properties of elements repeated after definite regular intervals or period. Mendeleeff arranged the elements in the increasing order of their atomic weights, in the form of a table, which is known as Mendeleeff's Periodic Table. In this the elements are arranged in groups (or columns) and periods (or rows). Defects of Mendeleeff's Periodic Table (1) Anomalous position of hydrogen: Mendeleeff has placed hydrogen in group IA, alongwith alkali metals, but at the same time, hydrogen also resembles halogens. Thus, the position of hydrogen is still a matter of dispute. (2) Similar pairs of elements, placed in different groups, while dissimilar elements placed in the same group: Many pairs of elements, which have similar properties with each other, have been placed in different groups. Examples are: Cu (IB)-Hg (IIB), Ag (IB-TI(IIIA), Ba (IIA)-Pb (IVA) etc. Many elements, which have dissimilar properties have been placed in the same group, e.g., coinage metals (IB: Cu, Ag and Au) have been placed along with alkali metals (IA). Similarly, Mn (VIIB) has been placed with halogens (VIIA). (3) Position of lanthanides and actinides: Lanthanides and actinides elements have not been placed in the main body of the Periodic Table. Rather these have been given a separate place at the bottom of the Periodic Table.
    [Show full text]