The Periodic Table of the Elements

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1 The Periodic Table of the Elements All matter is composed of elements. All of the elements are composed of atoms. An atom is the smallest part of an element which still retains the properties of that element.

2 All of the elements are listed on the Periodic Table by their Chemical Symbol The chemical symbol for every element is either one capital letter or one capital letter plus a small letter For example: C = carbon Ca = calcium Cl = chlorine Cr = chromium

3 Chemical Symbols Chemical Symbols represent name of element consist of one to two letters and start with capital 1-Letter Symbols 2-Letter Symbols C carbon Co cobalt N nitrogen Ca calcium F fluorine Al aluminum O oxygen Mg magnesium 3

4 Refer to Table 4.2 on Page 97 for list of the more common elements and their symbols.

5 All of the elements on the Periodic Table are arranged in vertical columns called Groups, and in horizontal rows called Periods. All of the groups have numbers and they are either A groups or B groups running from left to right on the Periodic Table

6 Periodic Table of the Elements Period Group** 1 IA 1A 18 VIIIA 8A 1 1 H IIA 2A 13 IIIA 3A 14 IVA 4A 15 VA 5A 16 VIA 6A 17 VIIA 7A 2 He Li Be B C N O F Ne Na Mg IIIB 3B 4 IVB 4B 5 VB 5B 6 VIB 6B 7 VIIB 7B IB 1B 12 IIB 2B 13 Al Si P S Cl Ar VIII K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc (98) 44 Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La* Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po (210) 85 At (210) 86 Rn (222) 7 87 Fr (223) 88 Ra (226) 89 Ac~ (227) 104 Rf (257) 105 Db (260) 106 Sg (263) 107 Bh (262) 108 Hs (265) 109 Mt (266) () () () () () () Lanthanide Series* 58 Ce Pr Nd Pm (147) 62 Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Actinide Series~ 90 Th Pa (231) 92 U (238) 93 Np (237) 94 Pu (242) 95 Am (243) 96 Cm (247) 97 Bk (247) 98 Cf (249) 99 Es (254) 100 Fm (253) 101 Md (256) 102 No (254) 103 Lr (257)

7 Learning Check Give the names of the elements with the following symbols: A. P B. Al C. Mn D. H E. K 7

8 Solution Give the names of the elements with the following symbols: A. P = phosphorus B. Al = aluminum C. Mn = manganese D. H = hydrogen E. K = potassium 8

9 Groups Columns of elements define element groups. Elements within a group share several common properties. Periods Rows of elements are called periods. The period numbers increase as you go from top to bottom on the periodic table. The number of elements in a period increases as you move down the periodic table.

10 Using grid coordinates (like a checkerboard) each element can be located on the Periodic Table. Refer to Figure #4.2 on Page 100

11 Solution Identify the element described by the following: 1. Group 7A, Period 4 bromine 2. Group 2A, Period 3 magnesium 3. Group 5A, Period 2 nitrogen 11

12 Learn the names of the groups: Ia = alkali metals IIa = alkaline earth metals All B groups = Transition metals VIIA = halogens VIIIA = noble (inert) gases

13 Classification of Groups Page

14 Refer to Page 102 Identify each of the following elements as metal, nonmetal, or metalloid. A. sodium metal B. chlorine nonmetal C. silicon metalloid D. iron metal E. carbon nonmetal 14

15 STRUCTURE OF THE ATOM: Particles that are smaller than the atom are called subatomic particles. The three main subatomic particles that form an atom are protons, neutrons, and electrons. The center of the atom is called the nucleus. Protons and neutrons make up the nucleus of an atom.

16 Atomic Number The atomic number is specific for each element. is the same for all atoms of an element. is equal to the number of protons in an atom. appears above the symbol of an element. Atomic Number Symbol 11 Na 16

17 Atomic number Si Mass number

18 An atom is the smallest part of an element which still retains the properties of that element. An isotope is another form of an element having a different number of neutrons.

19 An element's or isotope's atomic number tells how many protons are in its atoms. An element's or isotope's mass number tells how many protons and neutrons in its atoms.

20 Subatomic Particle Mass Electrical Charge P N e

21 Subatomic Particles in the Atom See Page Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 21

22 Protons have a positive electrical charge, so they are often represented with the mark of a "+" sign. Neutrons have no electrical charge

23 Learning Check Identify each statement as describing a 1) proton, 2) neutron, or 3) electron. A. found outside the nucleus B. has a positive charge C. is neutral D. found in the nucleus 23

24 Atomic Number The atomic number is specific for each element is the same for all atoms of an element is equal to the number of protons in an atom appears above the symbol of an element in the Periodic Table Atomic Number Symbol 11 Na Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 24

25 Every element, standing alone, in its neutral or uncombined state, MUST have an overall electrical charge of ZERO. That means that the number of electrons (negatives) must equal the number of protons (positives).

26 Atoms Are Neutral For neutral atoms, the net charge is zero. number of protons = number of electrons Aluminum has 13 protons and 13 electrons. The net (overall) charge is zero. 13 protons (13+) + 13 electrons (13 ) = 0 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 26

27 Composition of Some Atoms of Different Elements See Page 110 Table 4.6 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 27

28 Learning Check Use the periodic table to fill in the atomic number, number of protons, and number of electrons for each of the following elements: Element Atomic Number N Zn S Protons Electrons Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 28

29 Solution Use the periodic table to fill in the atomic number, number of protons, and number of electrons for each of the following elements: Element Atomic Number Protons Electrons N Zn S Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 29

30 Elements: Each element has a fixed number of positively charged protons in its nucleus and an equal number of electrons orbiting the nucleus. For example, hydrogen (H) has one proton and one electron, but lead (Pb) has 82 protons and 82 electrons. There are about 115 known elements of which 82 are naturally abundant.

31 Study Tips: Protons and Neutrons Number of protons = atomic number Number of protons + neutrons = mass number Number of neutrons = mass number atomic number Note: Mass number is given for specific isotopes only. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 31

32 Learning Check An atom of lead (Pb) has a mass number of 207. A. How many protons are in the nucleus? B. How many neutrons are in the nucleus? C. How many electrons are in the atom? Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 32

33 Solution An atom of lead (Pb) has a mass number of 207. A. How many protons are in the nucleus? atomic number = 82; number protons = 82 B. How many neutrons are in the nucleus? mass number number protons = number neutrons = 125 neutrons Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 33

34 Solution An atom of lead (Pb) has a mass number of 207. C. How many electrons are in the atom? An atom is neutral, which means that the number of electrons is equal to the number of protons. An atom of Pb has 82 protons and 82 electrons. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 34

35 This would be the Periodic Table Representation for the normal (stable) isotope of carbon: C 6 12 This indicates that the normal isotope of carbon has 6 protons and 6 neutrons

36 Atoms of the same element can have different numbers of neutrons; the different possible versions of each element are called isotopes.

37 Isotopes Isotopes are atoms of the same element have different mass numbers have same number of protons but different numbers of neutrons Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 37

38 Atomic Symbols and Subatomic Particles Examples of number of subatomic particles for atoms: Atomic symbol O P Zn p + 15 p + 30 p + 8 n 16 n 35 n 8 e - 15 e - 30 e - Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 38

39 Atomic Symbols for Isotopes of Magnesium Mass Numbers 24 Mg Mg Mg 12 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 39

40 Atomic Symbols for Isotopes of Magnesium Table 4.7 See Page 112 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 40

41 Learning Check Naturally occurring carbon consists of three isotopes: 12 C, 13 C, and 14 C. State the number of protons, neutrons, and electrons in each of the following: Isotope 12 C 13 C 14 C protons neutrons electrons Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 41

42 Solution Naturally occurring carbon consists of three isotopes: 12 C, 13 C, and 14 C. State the number of protons, neutrons, and electrons in each of the following: Isotope 12 C 13 C 14 C protons neutrons electrons Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright 2012 by Pearson Education, Inc. 42

43 Which element does X represent in the following symbol? X A.) mercury B.) chlorine C.) scandium D.) bromine E.) selenium Correct answer

44 Nuclear Notation Standard nuclear notation shows the chemical symbol, the mass number and the atomic number of the isotope.

45 14 6C 12 6C Normal Isotope This notation represents the isotope of carbon which has 8 neutrons, rather than 6 neutrons in the normal (stable)isotope

46 See Page 102

47 See Page 114

48 All atoms of any given element have the same mass. The mass of an element is the number beneath its chemical symbol on the periodic table. It represents the average mass of the isotopes that compose that element, weighted according to the natural abundance of each isotope of that element.

49 See Page 113 The atomic mass of chlorine is: 1.) due to all the Cl isotopes. 2.) not a whole number. 3.) the average of two isotopes: 35 Cl and 37 Cl.

50 Electrons spin and rotate around the outside of the nucleus. Only a certain number of electrons can be in an energy level at the same time. The octet rule says that atoms can only have a limited number of electrons in each electron shell.

51 Octet Rule: The first (innermost) shell is filled with 2 electrons. All of the rest of the shells are filled with 8 electrons

52 The octet rule: Shell Number Number of electrons (18) (32)

53 Helium atom model This helium (He) model displays two valence electrons located in its outermost energy level. Helium is a member of the noble gases and contains two protons, neutrons, and electrons.

54

55

56 The valence electrons are the electrons in the last shell or energy level of an atom. For the A Groups on the Periodic Table, the Group Number indicates the number of valence electrons for every element in that group. Elements in group IA have 1 valence electron. Elements in group IIA have 2 valence electrons.

57 The number of valence electrons of an element is determined by its periodic table group (vertical column) in which the element is categorized. FOR THE A GROUPS ONLY, the number of the group identifies how many valence electrons are contained within the elements listed under that particular column.

58 In the electron level arrangement for the first 18 elements electrons are placed in energy levels (1, 2, 3, etc.), beginning with the lowest energy level there is a maximum number in each energy level according to the octet rule. Energy level Number of electrons 1 2 (up to He) 2 8 (up to Ne) 3 8 (up to Ar) 4 2 (up to Ca) 58

59 Example: 1 The electronic configurations of some of the elements are detailed below. How many valence electrons do the following have? (a) Al : 2, 8, 3 (Group 3A) (b) Mg: 2, 8, 2 (Group 2A) (c) Cl : 2, 8, 7 (Group 7A) (d) Ca : 2, 8, 8, 2 (Group 2A)

60 Learning Check Write the electron level arrangement for each: N = 2, 5 Cl = 2, 8, 7 K = 2, 8, 8, 1 60

61 All atoms will tend to gain or lose electrons in order to complete their outer shell. Metals will generally lose their outer (valence) electrons to complete their outer shell. Nonmetals will tend to gain electrons to complete their outer shell. Metalloids may do either.

62 Recommended problems for chapter 4: Page # 4.7 through #4.12 Page # #4.16 Page # #4.30 Page # #4.34 Page # #4.36 Page # #4.46 Page # #4.90 Page # #4.100