Chapter Three Atomic Structure and the Periodic Table

Chapter 3 | Slide 2 Atomic Structure and the Periodic Table cont’d Recall our understanding of an element. Element is matter that ______ be broken down into a simpler substance by ________ or _________ means. Recall our understanding of an atom. Atom is the ________ particle of an element that can exist and still have the properties of the element.

Chapter 3 | Slide 3 Atomic Structure and the Periodic Table cont’d Now we will discuss ATOMIC STRUCTURE and Sub-Atomic Particles An atom is composed of a _______ and an area called the electron _____ »The nucleus is very small compared to the size of the atom »The nucleus contains the _______ (+) and the _______ »The __________ (-) are constantly moving around in the electron cloud »In a neutral atom, the number of electrons (-) is _______ to the number of protons (+)

Chapter 3 | Slide 4 ←Fig. 3.1 Nuclear Model of the Atom The protons and neutrons of an atom are found in the central nuclear region, or nucleus, and the electrons are found in an electron cloud outside the nucleus. Atomic Structure and the Periodic Table cont’d

Chapter 3 | Slide 5 Atomic Structure and the Periodic Table cont’d ElectronProtonNeutron Charge+10 Actual Mass (g) X X X Relative Mass e = 1 mass unit

Chapter 3 | Slide 6 Atomic Structure and the Periodic Table cont’d Atomic Symbols X QA Z Mass number = number of protons + number of neutrons Atomic number = number of protons Charge = number of protons – number of electrons

Chapter 3 | Slide 7 Atomic Structure and the Periodic Table cont’d # _________ = Atomic Number Z Atoms have no charge, # __________ = # __________ = Z # Neutrons = ______ Number (A) - # _________ (Z)

Chapter 3 | Slide 8 Atomic Structure and the Periodic Table cont’d Electrons are arranged around the nucleus of an atom Electrons can be _____ to, _______ from or _______ with other atoms When lost or gained, atoms become _______ (ions) Lost electrons result in _____charged ion, ________ Gained electrons result in _____ charged ion, _____ # Protons in nucleus ________ changes, _________ arrangement determine chemical properties

Chapter 3 | Slide 9 Atomic Structure and the Periodic Table cont’d Atomic Symbolvs Periodic Table Ca Ca 40.08

Chapter 3 | Slide 10 Atomic Structure and the Periodic Table cont’d How many electrons, neutrons, and protons are in the following particles? # protons#electrons#neutrons 40 Ca 40 Ca C 12 C

Chapter 3 | Slide 11 Atomic Structure and the Periodic Table cont’d # Protons remains constant # Neutrons can vary Mass numbers of atoms of same element will vary depending on the # neutrons in the nucleus Atoms that differ in # neutrons are called Isotopes

Chapter 3 | Slide 12 Atomic Structure and the Periodic Table cont’d Most elements have naturally occurring __________ Number of isotopes can range from two to ten Example: Silicon, Si exists in three isotopic forms All Si atoms have 14 protons and 14 electrons Most, 92.21% contain 14 neutrons Some, 4.70% contain 15 neutrons Some, 3.09% contain 16 neutrons

Chapter 3 | Slide 13 Atomic Structure and the Periodic Table cont’d They have the following notations Si Si 14 30

Chapter 3 | Slide 14 Atomic Structure and the Periodic Table cont’d The additional neutrons in the nucleus may have very slight effects on the chemical properties of the element, and some measurable effects on some physical properties such as melting points, boiling points and Densities. See Chemical Connections on pg 55 in text.

Chapter 3 | Slide 15 Atomic Structure and the Periodic Table cont’d The atomic mass is expressed in atomic mass units amu atomic mass unit Defined as 1/12 th the mass of 12 C 1 amu = the mass of 1 proton or 1 neutron The atomic mass that is found on the periodic table or used for calculations is a weighted average of the atomic masses for the isotopes

Chapter 3 | Slide 16 Atomic Structure and the Periodic Table cont’d To get the average mass of an element, you must add together the mass contributions of each different isotope »% abundance x isotopic mass = mass contribution Calculate the average atomic mass of Chlorine if 75.53% of the atoms are 35 Cl (34.97 amu) and 24.47% of the atoms are 37 Cl (36.97 amu). ( x amu) + ( x amu) = amu

Chapter 3 | Slide 17 Atomic Structure and the Periodic Table cont’d

Chapter 3 | Slide 18 Atomic Structure and the Periodic Table cont’d →Table 3.2 Isotopic Data for Elements with Atomic Numbers 1 through 12

Chapter 3 | Slide 19 Atomic Structure and the Periodic Table cont’d Early 1800s, scientists searched for some order in the chemical information known at that time Certain elements had properties that were very similar to those of other elements Method or Arrangement was sought that would be consistent with this information

Chapter 3 | Slide 20 Atomic Structure and the Periodic Table cont’d John Newlands (1865) Arranged elements in order of increasing atomic mass When he did this, he noticed that there were chemical and physical properties that repeated every eight elements “law of octaves”

Chapter 3 | Slide 21 Atomic Structure and the Periodic Table cont’d → Fig. 3.2 Mendeleev constructed a periodic table as part of his effort to systemize chemistry. Edgar Fahs Smith Collection, University of Pennsylvania Library

Chapter 3 | Slide 22 Atomic Structure and the Periodic Table cont’d Dmitri Mendeleev and Julius Lothar Meyer independently proposed ideas or relationships regarding the periodicity of __________ and increasing atomic ________ or atomic _________. Modern Periodic Law states that when elements are arranged in order of increasing atomic number, elements with similar chemical properties occur at periodic or regularly recurring intervals.

Chapter 3 | Slide 23 Novastock/PhotoEdit Atomic Structure and the Periodic Table → CO 3.1 Music consists of a series of tones that build octave after octave. Similarly, elements have properties that recur period after period.

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Chapter 3 | Slide 25 Atomic Structure and the Periodic Table cont’d Elements with similar chemical properties are positioned in _________ ___________ These _________ _________ are called ________ The ____________ ______ of elements are called ____________ Note the _________ are numbered sequentially 1-7 The ________ are identified by two notations, using Roman numerals and letters, or numbered sequentially 1-18

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Chapter 3 | Slide 28 Atomic Structure and the Periodic Table cont’d Also note that Element 72 follows Element 57, as does Element 104 follows Element 89 The missing elements 58 through 71 and 90 through 103 are located in two rows at the bottom of the periodic table. Positioned here for convenience. See the periodic table in the next slide with these rows positioned where they should be located.

Chapter 3 | Slide 29 Atomic Structure and the Periodic Table cont’d Fig. 3.4 In this periodic table, elements 58 through 71 and 90 through 103 are shown in their proper positions.

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Chapter 3 | Slide 31 Atomic Structure and the Periodic Table cont’d Common Names for some Groups Group IA – Alkali Metals, excluding H Soft, shiny and readily react with water Group IIA – Alkaline earth metals Soft, shiny and moderately reactive toward water Group VIIA – Halogens Reactive, colored, gases at or slightly above room temperatures Group VIII – Nobel Gases Generally unreactive, that undergo few, if any, chemical reactions

Chapter 3 | Slide 32 Atomic Structure and the Periodic Table cont’d

Chapter 3 | Slide 33 Atomic Structure and the Periodic Table cont’d (a)Some familiar metals are aluminum, lead, tin, and zinc. (b) Some familiar nonmetals are sulfur, phosphorus, and bromine. Fig. 3.5

Chapter 3 | Slide 34 Atomic Structure and the Periodic Table cont’d ←Fig. 3.6 This portion of the periodic table shows the dividing line between metals and nonmetals.

Chapter 3 | Slide 35 Atomic Structure and the Periodic Table cont’d Electrons are arranged around the nucleus of an atom Electrons can be lost to, gained from or shared with other atoms When lost or gained, atoms become charged (ions) Lost electrons result in + charged ion, cation Gained electrons result in – charged ion, anion Inference: Electrons are special and we will learn are related to the chemical properties of an element

Chapter 3 | Slide 36 Atomic Structure and the Periodic Table cont’d The space outside the nucleus in an atom is called the ___________ ____________ »The _________ ________ is subdivided into different ___________ (positioned according to energy each electron possesses Shells are subdivided into ____________ ›Subshells are subdivided into __________ ○Each orbital contains _____ electrons

Chapter 3 | Slide 37 Atomic Structure and the Periodic Table cont’d Electron Shell »A region of space about a nucleus that contains electrons that have approximately the same energy and that spend most of their time approximately the same distance from the nucleus 1 st shell »Can contain up to 2 electrons 2 nd shell »Can contain up to 8 electrons 3 rd shell »Can contain up to 18 electrons 4 th shell »Can contain up to 32 electrons Any shell can contain up to 2n 2 electrons, where n is the shell number

Chapter 3 | Slide 38 Atomic Structure and the Periodic Table cont’d Subshell »A region of space within an electron shell that contains electrons that have the same __________ »Four different kinds of subshells: s, p, d, and f »Shell 1: contains s subshell »Shell 2: contains s and p subshells »Shell 3: contains s, p, and d subshells »Shell 4: contains s, p, d, and f subshells

Chapter 3 | Slide 39 → Fig. 3.7 The number of subshells within a shell is equal to the shell number. Atomic Structure and the Periodic Table cont’d

Chapter 3 | Slide 40 Atomic Structure and the Periodic Table cont’d Orbital »Region of space where two electrons are found »Have different shapes depending on which subshell they are in (shape of region of space not electrons) »There are a different number of orbitals in each kind of subshell In an s subshell, there is 1 orbital In a p subshell, there are 3 orbitals In a d subshell, there are 5 orbitals In a f subshell, there are 7 orbitals

Chapter 3 | Slide 41 Atomic Structure and the Periodic Table cont’d Fig. 3.8 An s orbital has spherical shape; a p orbital has two lobes; a d orbital has four lobes; and an f orbital has eight lobes.

Chapter 3 | Slide 42 Atomic Structure and the Periodic Table cont’d Fig. 3.9 Orbitals within a subshell differ mainly in orientation.

Chapter 3 | Slide 43 Atomic Structure and the Periodic Table cont’d There are ____ electrons in each ________ »The electrons move around in the __________ »One of the electrons spins __________ »One of the electrons spins ______________________

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Chapter 3 | Slide 45 Atomic Structure and the Periodic Table cont’d Electron configurations tells us in which subshells the electrons for an element are located. Three rules: »1. Electrons fill orbitals starting with lowest energy first »2. There can be no more than 2 electrons in any orbital, and those electrons must have different spins »3. For orbitals in the same subshell, electrons fill each orbital singly before any orbital gets a second electron

Chapter 3 | Slide 46 Atomic Structure and the Periodic Table cont’d ←Fig The order of filling various electron subshells. Subshells of different shells “overlap.” How will you remember the order?

Chapter 3 | Slide 47 Atomic Structure and the Periodic Table cont’d →Fig The order of filling various electron subshells with electrons follows the same order given by the arrows in this diagram.

Chapter 3 | Slide 48 Atomic Structure and the Periodic Table cont’d Writing Electronic Configurations H 1s 1 He 1s 2 Li 1s 2, 2s 1 Ne 1s 2, 2s 2, 2p 6 Na 1s 2, 2s 2, 2p 6, 3s 1 Ar 1s 2, 2s 2, 2p 6, 3s 2, 3p 6 K 1s 2, 2s 2, 2p 6, 3s 2, 3p 6, 4s 1 K [Ar] 4s 1 Kr 1s 2, 2s 2, 2p 6, 3s 2, 3p 6, 4s 2, 3d 10, 4p 6 Kr [Ar] 4s 2, 3d 10, 4p 6

Chapter 3 | Slide 49 Atomic Structure and the Periodic Table cont’d Electronic Configurations of Transition Elements Fe 1s 2, 2s 2, 2p 6, 3s 2, 3p 6, 4s 2, 3d 6 Br 1s 2, 2s 2, 2p 6, 3s 2, 3p 6, 4s 2, 3d 10, 4p 5 Pb 1s 2, 2s 2, 2p 6, 3s 2, 3p 6, 4s 2, 3d 10, 4p 6, 5s 2, 4d 10, 5p 6, 6s 2, 4f 14, 5d 10, 6p 2

Chapter 3 | Slide 50 Atomic Structure and the Periodic Table cont’d Which of the following electron configurations is correct for »A) »B) »C) »D) »E)

Chapter 3 | Slide 51 Atomic Structure and the Periodic Table cont’d Give the symbol of the element that has: A. [Ar]4s 2 3d 6 B. Four 3p electrons C. Two electrons in the 4d sublevel D. The element that has the electron configuration 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 2 1s 2 2s 2 2p 6 3s 2 3p 6 3d 4

Chapter 3 | Slide 52 Atomic Structure and the Periodic Table cont’d Drawing Orbital Diagrams First, write out the electron configuration Start drawing the orbital diagram »--1 orbital (blanks) for every s subshell »--3 orbitals(blanks) for every p subshell »--5 orbitals (blanks) for every d subshell Blanks are circles or squares

Chapter 3 | Slide 53 Atomic Structure and the Periodic Table cont’d Orbital Diagrams Li Na Na 1+ 1s 2 2s 1 2p 3s 3p 1s 2 2s 2 2p 6 3s 1 3p ↑↓↑ 1s 2 2s 2 2p 6 3s 3p ↑

Chapter 3 | Slide 54 Atomic Structure and the Periodic Table cont’d Orbital Diagrams N O O 2- 1s 2 2s 2 2p 3 3s 3p 1s 2 2s 2 2p 4 3s 3p ↑↓ ↑↑ 1s 2 2s 2 2p 6 3s 3p ↑↓↑↑↑

Chapter 3 | Slide 55 Atomic Structure and the Periodic Table cont’d ←CC 3.3 The different colors of fireworks result when heat excites the electrons of different kinds of metal atoms. William S. Helsel/Getty Images

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Chapter 3 | Slide 57 Atomic Structure and the Periodic Table cont’d Electron Configuration and the Periodic Law We said that elements in the same group have similar chemical reactivities »Electrons are the subatomic particles involved in chemical reactions Which electrons are most likely to be involved in chemical reactions? »A) those nearest to the nucleus »B) those farthest from the nucleus »C) all are equally likely to be involved

Chapter 3 | Slide 58 Atomic Structure and the Periodic Table cont’d What differentiates one family from another? »Let’s look at the electron configurations (valance electron configurations) of the alkali metals to find out. Li Na K Rb Cs Fr

Chapter 3 | Slide 59 Atomic Structure and the Periodic Table cont’d Elements with similar properties have the same type of distinguishing electron! (_________ electrons) The last electron added to the electron configuration for an element when electron subshells are filled in order of increasing energy It is also the one that causes an element’s electron configuration to differ from that of the element immediately preceding it in the periodic table

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