Unit 3: Periodic Table Have your Periodic Table out everyday for this unit

I. Historical Development of the Table A. Dmitri Mendeleev (__________) Arranged elements into table based on… similarities in the physical and chemical properties thought similarities were function of atomic mass Noticed that some elements seemed out of order (Iodine and Tellurium) Mendeleev Video Clip

I. Historical Development of the Table 1913 B. Henry Mosely (__________) Established that properties of elements were functions of ____________ Atomic Number 1. Present table based on ________________ Atomic Number 2. Elements’ properties depend on ________________ Structure of atom 3. Properties of elements vary ________________ Systematically throughout the table

I. Historical Development of the Table C. Periodic Law: When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

II. Period (or Rows) Horizontal rows Number at the beginning of the period indicates the number of energy levels 1 2 3 Periods 

II. Period (or Rows) 4 Properties change as you move across a period Example: A) What period is potassium and bromine in? ____ ____________________________________________ 4 Properties change as you move across a period

III. Groups(or Families) Vertical Columns Each group has similar chemical properties For representative elements (A) the group number tells you the number of valance electrons Group 1A has 1 valance electron Group 3A has 3 valance electrons

Valance electrons are electrons found in the outermost energy level of an atom

II. Period (or Rows) 2 Similar (both have 2 valence e-) Example: A) What group is magnesium and calcium in? ____ B) Based on the group, how do the properties of magnesium and calcium compare? _______________ 2 Similar (both have 2 valence e-)

III. Groups(or Families) Sample Questions: Which sequence of atomic numbers represents elements which have similar chemical properties? A) 19, 23, 30, 36 C) 9, 16, 33, 50 B) 3, 12, 21, 40 D) 4, 12, 38, 88   Which two elements have the most similar chemical properties? A) Aluminum and Barium C) Nickel and Phosphorous B) Chlorine and Sulfur D) Sodium and Potassium

Forming Cations & Anions IONS are atoms or groups of atoms with a positive or negative charge. A CATION is positively charged and forms when an atom loses one or more electrons An ANION is negatively charged and forms when an atom gains one or more electrons Mg --> Mg2+ + 2 e- F + e- --> F-

PREDICTING ION CHARGES In general metals lose electrons and form cations nonmetals gain electrons and form anions

VI. Ions An atom that has lost or gained electrons (# of protons does NOT EQUAL # of electrons) 2311 Na +1 # of p = # of n = # of e- = 11 Mass # = Atomic # = Ion Charge = 23 23 – 11 = 12 11 Atomic # - Ion Charge +1 # of e- = 11- (+1) = 10

VI. Ions Examples: 3 15 16 18 Mass # - Atomic # Atomic # - Charge Lost e- (cation) 3 7 – 3 = 4 3 – (+1) = 2 7 Li + 1 ______ p ________ n ____________ e ________ 31 P – 3 ______ p ________ n ________ e ___________ 79 Se – 2 ______ p ________ n ________ e ___________ 39 K + 1 ______ p ________ n ________ e ___________ Gained e- (anion) 15 16 18 34 45 36 gained e- (anion) 19 20 18 lost e- (cation)

IV. Metals- Outline green Atoms that lose e- and form positive ions (cations) when bonding Alloy: Mixture of metals by melting them together (can use pg 158 or back of book to see elements better)

IV. Metals 1. Low ionization energy and electronegativity Properties of Metals: 1. Low ionization energy and electronegativity 2. Good conductors of heat and electricity 3. Exhibit metallic luster (shine) 4. Malleability (can be pounded into thin sheets) 5. Ductility (can be pulled into thin wires) 6. More than 2/3 of the elements are metals 7. High densities 8. Mercury (Hg) is a metal which a liquid at room temperature.

CHECKS FOR UNDERSTANDING IV. Metals CHECKS FOR UNDERSTANDING Which element is malleable and can conduct electricity in the solid phase? A) Iodine B) Phosphorous C) Sulfur D) Tin

V. Nonmetals- Outline red atoms gain e- and form negative ions (anions) when bonding (can use pg 158 or back of book to see elements better)

V. Nonmetals 1. High ionization energy and electronegativity Properties of Nonmetals: 1. High ionization energy and electronegativity 2. Poor conductors of heat and electricity 3. Brittle and hard 4. Low densities 5. Many are gases Graphite is an allotrope of carbon. It is used in pencils (brittle, soft, and low density)

CHECKS FOR UNDERSTANDING V. Nonmetals CHECKS FOR UNDERSTANDING Which element is brittle and not a conductor of electricity? A) Sulfur B) Sodium C) Potassium D) Argon

VI. Metalloids – Outline purple Atoms that gain or lose e- and form ions when bonding Have properties of both metals and nonmetals Can be located using the “staircase” (see periodic table) Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Astatine (can use pg 158 or back of book to see elements better)

CHECKS FOR UNDERSTANDING VI. Metalloids CHECKS FOR UNDERSTANDING Which element has both metallic and nonmetallic properties? A) Rb B) Rn C) Si D) Sr Which list of elements contains 2 metalloids? Si, Ge, Po, Pb C) As, Bi, Br, Kr Si, P, S, Cl D) Po, Sb, I, Xe

VIII. Groups within Groups A. Group 1A/1: ________________ Alkali Metals- Color green All soluble (dissolves) in water and strongly basic Hydrogen is the exception on the periodic table – it belongs nowhere : ( ALKALI METALS- clip

VIII. Groups within Groups Alkaline Earth Metals- color light green B. Group 2A/2: ______________________ Reactive with water and air, but less reactive than group 1A In General for Groups 1 and 2: As you move down, they become more reactive

VIII. Groups within Groups Transition Metals color blue C. Groups B’s/3-12: ________________ Dense Metals and high melting points Form multiple ions and less reactive than Groups 1 and 2 Form ions that have color Copper (II) Sulfate Solution (Cu2+ ions) Cobalt (II) Chloride Solution (Co2+ ions)

VIII. Groups within Groups CHECKS FOR UNDERSTANDING 4. Identify the metal that has multiple oxidation states. A) K B) Ba C) Be D) Pd 5. Which compound forms a green aqueous solution? A) RbCl B) CaCl2 C) NiCl2 D) BeCl2 6. Which set of properties is most characteristic of transition elements? Colorless ions in solutions, multiple positive oxidation states Colorless ions in solutions, multiple negative oxidation states Colored ions in solutions, multiple negative oxidation states Colored ions in solutions, multiple positive oxidation states

VIII. Groups within Groups Halogens- color orange D. Group 7A/17: ________________ Most reactive nonmetals, especially with group 1A Mostly nonmetallic elements

VIII. Groups within Groups E. Group 8A/18: ________________ Noble Gases- color red Have 8 valence electrons (or 2 for He) Have a full outer energy level Do not react because their outer shell is completely full (8) They are stable (do not react easily because their out shell is full ALL OTHER ELEMENTS WANT TO BE LIKE THEM

Others Color the rest of the nonmetals yellow Color the rare earth metals (bottom two rows) brown

X. Other Categories Diatomics - Molecule containing 2 identical atoms Remember them: BrINClHOF H, O, F, Br, I, N, Cl (7-H club) Radioactive - Nucleus is unstable and breaks down spontaneously (all isotopes are radioactive, but less than the ones mentioned below) Which ones? Atomic # greater than 84 also 43 (Technetium) and 61 (Promethium)

X. Other Categories Synthetic – (NOVA: How they are made) Man-made elements (all are radioactive, as well, but disintegrate in milliseconds) Remember them: Atomic # greater than 93 also 43 (Technetium) and 61 (Promethium) White on my periodic table

VII. Periodic Properties A. Atomic Radius: Distance between the center of the nucleus to the most outer electron shell (orbital)

VII. Periodic Properties Periodic Trend (See Ref Tabs – Table _____) decreases Covalent Atomic Radius ___________ as you move from ______________________________ Left to right across a period PEL remains the same and outer e- get pulled closer to the nucleus increases Covalent Atomic Radius ___________ as you move from ______________________________ down a group # of energy levels increase

VII. Periodic Properties B. Ionic Radius: A loss or gain of e- causes an increase or reduction in atom’s size Metals: __________ electrons when they form ions ( _____________ ) and ionic radius __________ than neutral atom lose cations smaller 2-8-1 2-8

VII. Periodic Properties B. Ionic Radius: Nonmetals: __________ electrons when they form ions ( __________ ) and ionic radius __________ than neutral atom anions gain bigger 2-8-7 2-8-8

IV. Periodic Properties Sample Questions: Which element has an atomic radius that is greater than its ionic radius? A) S C) F B) K D) O In period 4, the atom with the largest covalent radius is located in group… A) 1 C) 3 B) 13 D) 18

VII. Periodic Properties C. Ionization Energy: Amount of energy needed to remove the most loosely bound e - (valence e -)

VII. Periodic Properties Periodic Trend (See Ref Tabs – Table _____) increases Ionization Energy ___________ as you move from ______________________________ Left to right across a period Number of protons and valence e- increases and size decreases, so e- are held tighter decreases Ionization Energy ___________ as you move ______________________________ down a group (e- are farther away, so easier to remove e- Electron Shielding (see board)

VII. Periodic Properties D. Electronegativity: Measure of atom’s attraction for electrons when bonded Desire of an atom to gain electrons Periodic Trend (See Reference Tables – Table _____): Electronegativity ______________ as you move from ______________________________ Electronegativity ______________ as you move from _____________________________ S increases Left to right across a period decreases down a group

IV. Periodic Properties Check for Understandings What are the electronegativity's for group 18 elements? Why do you think they have “this” electronegativity? Which element attracts electrons the most when bonding? A) Ca C) Br B) Sr D) I Which element gives off its valence electrons the easiest? A) Ca C) Br B) Sr D) I They do not have electronegativity numbers. Why? Because they already have their 8 valence electrons (octet)

VIII. Groups within Groups CHECKS FOR UNDERSTANDING As you move down groups 1 and 2 elements become more reactive. Explain why this happens based on atomic size and ionization energy/electronegativity. What will be the charge on a Ca ion when it bonds? Based on your answer to question 2, what happens to the atomic size once it becomes an ion? As atomic size increases, ionization energy decreases (easier to remove e-) so they become more reactive +2 Smaller (loses last energy level)

VIII. Groups within Groups CHECKS FOR UNDERSTANDING Which halogen is most reactive? Explain why, based on atomic size, electronegative/ionization energy. Explain why noble gases don’t typically react with other elements? F: smallest in size so attraction for electrons is very high (electronegativity) Their outer energy level is completely full. They do not want to gain anymore e-