“A” students work (without solutions manual) ~ 10 problems/night .

“A” students work (without solutions manual) ~ 10 problems/night. Alanah Fitch Flanner Hall 402 508-3119 afitch@luc.edu Office Hours W – F 2-3 pm Module #3 Atoms, Molecules And Ions

Atoms, Molecules and Ions Atoms – Intro to Periodic Table Molecules – Representations and Formulas Ions Naming Rules

J. J. Thomson English Math/physicist 1856-1940 1897 J. J. Thomson showed that electricity passed through low pressure gases emitted light which could be “bent”. Relative Particle Symbol Charge Mass Discovery Electron e - 0.00055 1897 Proton p + 1.00728 1911 Neutron n uncharged 1.00728 1911 Factor of 2000

0.00055 Electron outside nucleus RELATIVE MASSES n p 1.00728 Neutron, n Proton, p nucleus

n n n n n n p p p p p p p Element Hydrogen D Hydrogen Helium He Lithium, Li Symbol H Number of Protons? 3 1 1 2 The number of protons, Z, is a basic property of an element: The Atomic Number Deuterium and Hydrogen are the same element!!!

Hydrogen Element Hydrogen Lithium, Helium Li H D Symbol He Z 1 1 2 3 # Neutrons 2 0 1 3 Mass number A? 1 2 4 6 The mass number, A, is the sum of neutrons and protons

FITCH Rules G1: Suzuki is Success G2. Slow me down G3. Scientific Knowledge is Referential G4. Watch out for Red Herrings G5. Chemists are Lazy C1. It’s all about charge C2. Everybody wants to “be like Mike” (grp.18) C3. Size Matters C4. Still Waters Run Deep C5. Alpha Dogs eat first General Shorten up the notation Chemistry

Deuterium Element Hydrogen Lithium, Helium Li H D Symbol He Z 1 1 2 3 # Neutrons 2 0 1 3 Mass number A? 1 2 4 6 Nuclear Symbol The mass number, A, is the sum of neutrons and protons

Formation of Stable Isotopes (Nucleosynthesis from Stellar Reactions) n n n n n n n n n p p p p p p p p p p p p p p p p p n n n n n n n n Read Chapter 19.1, box p. 523 neutron n (High speed electron) n p proton No electrons are shown because they are in a sea at high temperature and pressure. Shown are the nuclei p deuterium n Helium particle Berylium

What do you “see”? 1 2 8 6 10 12 7 13 11 9 3 5 4

n n n n n p p p p p p p p p n n n n neutron n (High speed electron) n p proton Each Increase Involves Forcing Together More Highly Charged components p p deuterium n Abundance of even mass reflects the role of Helium, an alpha particle, in nuclear synthesis Helium particle Berylium Abundance decreases Exponentially because Of charge repulsion Within the nucleus

FITCH Rules G1: Suzuki is Success G2. Slow me down G3. Scientific Knowledge is Referential G4. Watch out for Red Herrings G5. Chemists are Lazy C1. It’s all about charge C2. Everybody wants to “be like Mike” (grp.18) C3. Size Matters C4. Still Waters Run Deep C5. Alpha Dogs eat first General Chemistry

An Analogy: Magnets Opposite poles attract attraction Total interaction increases with? Size of magnet repulsion Shorter distance between Objects Similar poles repel

It’s all about charge Charge on object 1 or 2, in coulombs Distance between the objects Unit of electrical charge, A coulomb Charles Augustin Coulomb 1735-1806 French, trained as army Engineer, particularly Interested in friction

It Takes energy to push these guys together Repulsion Positive energy + + - + Attraction Negative energy

d The potential energy is largest when the two objects are touching d is then the sum of each radii As Q goes up attraction/repulsion Goes up

Neutrons are the “glue” which hold the nucleus together. They prevent high charged protons from repelling each other and thus causing fission or breaking apart of the nucleus. Even more nuetrons, n Chemistry Rule #1 = it’s all about Charge After about 20 protons more and more neutrons are necessary to “glue” the nucleus together. Eventually not enough neutrons can be added and the nucleus is unstable. Increase number of protons, z One of the last stable elements is LEAD. Many unstable elements decay to lead.

Generally Speaking Decrease in Abundance with Z Higher than Expected Abundance of lead

n n n n n n n n n n n n n n n n n n n p p p p p p p p p p p p p p p p p p p p p Unstable elements undergo radioactive decay High energy radiation gamma rays also released Conversion of a neutron to a proton is accompanied by release of a beta particle, identical in property to an electron Whoa Nelly, doesn’t this just make things worse? Beta particle emission Follow up with expulsion of protons

n n n n n n n n p p p p p p p p n p Unstable elements undergo Radioactive Decay The Helium nucleus is known as an “alpha” particle =2 protons + 2 neutrons p p Alpha particle emission

Fission of the unstable elements results in “transmutation” Stellar Reaction Formed This Stable isotope

Greek: Iso – same topos – place Same place in period table = same element There are four stable isotopes of lead An element has a fixed number of protons (Atomic Number=Z). An element may have variable number of neutrons. An isotope is an atom of an element with a different number of neutrons. (Like hydrogen and Deuterium) The mass number, A, of isotopes (# protons + # neutrons) will differ Z 82 82 82 82 #neutrons 122 124 125 126 A 204 206 207 208 + + + + Pb-204 Pb-206 Pb-207 Pb-208 = = = =

Formation of Stable Isotopes (Nucleosynthesis from Stellar Reactions): More n n n n n n n n n n n n n n n n n n p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p n n n n n n n n n n n n n n n n n n n Read Chapter 19.1, box p. 523 p Upper atmosphere reaction (High energy light) (High speed electron) This will be our Atomic mass reference state Stable Isotopes of Carbon % Abundance Mass 98.89 12.0000 1.11 13.00335 What are Fitch General Rules 1 - 5?

FITCH Rules G1: Suzuki is Success G2. Slow me down G3. Scientific Knowledge is Referential G4. Watch out for Red Herrings G5. Chemists are Lazy C1. It’s all about charge C2. Everybody wants to “be like Mike” (grp.18) C3. Size Matters C4. Still Waters Run Deep C5. Alpha Dogs eat first General Chemistry

There are distinct “periods” in the fluctuation of elemental abundance. 1 2 Row 1 Row 2

These “periods” are symbolized in the Periodic Table as rows Abundance crashed between row 1 and 2 1 2 3 4 It takes hugely more energy to put in another proton (and electron) to get Li! Similar peak/valley noted after Ne, Abundance is related to stable atomic configuration By this I mean stable charge of electrons with respect to protons!!!! Periodic table is arranged to convey this information Next: Explore the Geography Of the Periodic Table

Groups periods 1 18 1 2 3 4 5 6 2 13 14 15 16 17 3 4 5 6 7 8 9 10 11 12 Elements within a Group have similar chemical properties

Main-Group Element Noble Gases 1 Chalcogens 1 2 3 4 5 6 Metalloids 2 13 14 15 16 17 Post-Transition Metals Alkali metals Transition Metals 3 4 5 6 7 8 9 10 11 12 Alkaline Earth Metals Halogens Coinage Metals

Atoms, Molecules and Ions Atoms – Intro to Periodic Table Molecules – Representations and Formulas Ions Naming Rules Atom - Smallest particle of an element that can enter into a CHEMICAL REACTION. Most atoms react with each other to form complex structural units Two complex structural units are Molecules Ions

Representations of Molecules 1. Molecular Formulas Number of atoms of each element indicated by subscript following elemental symbol H2O - water has NH3 - ammonia has CH4 - methane has 2 atoms of H and 1 atom of O 1 atom of N and 3 atoms of H 1 atom of C and 4 atoms of hydrogen 2. Structural Formulas Shows the bonding patterns

Representations of Molecules 1. Molecular Formulas 2. Structural Formulas Shows the bonding patterns H-O-H H2O water H H-C-H H CH4 methane H-N-H H NH3 Ammonia Molecular Formula Common Name

Representations of Molecules 1. Molecular Formulas 2. Structural Formulas 3. Condensed Structural Formula a. Gives number of atoms b. Suggests bonding pattern CH4O methyl alcohol H H-C-O-H H CH3OH CH5N methylamine H H-C-N-H H H CH3NH2 Condensed Structural Formula indicates the reactive group

> 2 atoms may combine to form uncharged molecules • 1. Usually nonmetallic elements combine to share electrons • in what is termed “covalent” bonding (more later) • Some elements combine with themselves to create single element compounds (molecular elements) Red boxes are ones you Will see over and over Memorize! H2(g) N2(g) O2(g) F2(g) P4(s) S8(s) Cl2(g) Br2(g) I2(g) Chemistry Rule #1 = it’s all about Charge

n n n n n n n n n n n n n n p p p p p p p p p p p p p p - Electron outside nucleus + Remove e p p atom is charged Alternatively Add e

GRAMMAR and LANGUAGE Ion From Greek “ienai” to go Cat From Greek - Cat = down An From Greek - An = up Definition relates to the manner in which charge (positive vs negative) was discovered. Current goes down (into solution) or Current goes up (out of solution) mnemonic Cation: Positively Charged Ion (has lost electrons) Anion: Negatively Charged Ion (has gained electrons) That which defines an element (number of protons) remains constant!!!!

FITCH Rules G1: Suzuki is Success G2. Slow me down G3. Scientific Knowledge is Referential G4. Watch out for Red Herrings G5. Chemists are Lazy C1. It’s all about charge C2. Everybody wants to “be like Mike” C3. Size Matters C4. Still Waters Run Deep C5. Alpha Dogs eat first General Chemistry

Circled element is much more abundant than the next, indicating it takes significant more energy to create the next element

Capturing a few electrons lets these guys act like noble gases and get to one of those peak stabilities we saw in the natural abundance Losing a few electrons here lets these guys look like those stable noble gases Non-metals are Anion Formers Alkali metals (Group 1) for single charged cations: H+, Li+, Na+ Most common anions are groups 16 and 17 because they only need to capture 2 (group 16) and 1 (group 17) electrons Alkaline earth metals (Group 2) for double charged cations: Mg2+, Ca2+, Sr2+

Losing a few electrons here let’s these guys look like this “break” • Transition Metals attempt to follow rules • It’s all about charge and • Be like mike (satisfy nuclear charge) This puts them between a rock And a hard place Because Rule 2 makes them too highly Net charged which violates Rule 1

Losing a few electrons here let’s these guys look like this “break” These guys can’t “be like mike” so they settle For second or third best Losing a few electrons here lets these guys Get ½ a loaf

Ojo! – these guys can Do both! = a reason Why they are so Important in biology! +4 1- 2-

Alpha-PbO Pb3O4 Beta-PbO PbO2 Example: Give the number of protons, neutrons, and electrons in , cations found in the lead oxides used in car batteries

Strategy 1. Convert words to symbols on left hand side of the paper. 2. Mark the unnecessary information as red herrings. 3. Random associate with any equations or relationships you can remember. Write those equations down on the left hand side of the paper. 4. Check the equations symbols for various known and unknown symbols required. Choose equation which had unknown with most knowns. 5. Solve.

Example: Give the number of protons, neutrons, and electrons in , cations found in the lead oxides and sulfates used in car batteries known # protons # neutrons # electrons lead oxides lead sulfates car batteries

Example: Give the number of protons, neutrons, and electrons in , cations found in the lead oxides and sulfates used in car batteries A, mass number, number of (protons plus neutrons) Z, atomic number, number of protons Charge on the ion Number electrons in atom = number of protons Number electrons in ion= number of electrons in atom – (charge) 82 electrons - 2 = 80 electrons

Example: Give the number of protons, neutrons, and electrons in , cations found in the lead oxides and sulfates used in car batteries Protons Neutrons Electrons 82 124 80 82 124 78 -2 more e 2+

> 2 atoms may combine to form uncharged molecules • 1. Usually nonmetallic elements combine to share electrons • in what is termed “covalent” bonding (more later) • Some elements combine with themselves to create single element compounds • Charged elements can combine to form uncharged molecules What are Fitch Rules C1 & C2?

“A” students work (without solutions manual) ~ 10 problems/night .