Do you know your atomic structure?
Basic Unit of Matter ATOM Sodium Atom Animation
What is the charge of each subatomic particle?
Proton neutron electron O positive none negative
Where are they found in the atom?
Neutron and proton – in the nucleus Electron –outside the nucleus Helium atom animation
Pure Substance: Iodine
Element Song(link) “The Elements” by Tom Lehrer
There’s antimony, arsenic, aluminum, selenium, And hydrogen and oxygen and nitrogen and rhenium And nickel, neodymium, neptunium, germanium, And iron, americium, ruthenium, uranium, Europium, zirconium, lutetium, vanadium And lanthanum and osmium and astatine and radium And gold, protactinium and indium and gallium And iodine and thorium and thulium and thallium. There’s yttrium, ytterbium, actinium, rubidium And boron, gadolinium, niobium, iridium And strontium and silicon and silver and samarium, And bismuth, bromine, lithium, beryllium and barium. There’s holmium and helium and hafnium and erbium And phosphorous and francium and fluorine and terbium And manganese and mercury, molybdinum, magnesium, Dysprosium and scandium and cerium and cesium And lead, praseodymium, platinum, plutonium, Palladium, promethium, potassium, polonium, Tantalum, technetium, titanium, tellurium, And cadmium and calcium and chromium and curium. There’s sulfur, californium and fermium, berkelium And also mendelevium, einsteinium and nobelium And argon, krypton, neon, radon, xenon, zinc and rhodium And chlorine, cobalt, carbon, copper, Tungsten, tin and sodium. These are the only ones of which the news has come to Harvard, And there may be many others but they haven’t been discovered.
Symbols of Elements 1. First letter is capitalized
2. Second letter (if there is one) is always lower case EXAMPLES: C F Al Cl B Mn Ca H Mg Cr O Mo
Which are symbols? Abbreviations for elements
C CO Mn CO Ni Why? C Mn Ni Only one capital letter
Trace Elements Needed by some organisms but only in very small amounts
Like iodine, we need only 0.15 mg per day A deficiency will cause a goiter
What are trace elements?
Needed in the body in only small amounts Like mg (milligrams) WHY IMPORTANT IF WE DON’T NEED SO MUCH? Minerals act as catalysts (speed up reactions) for many biological reactions
EACH ELEMENT: All the same atoms
Photographic Periodic Table (link)
Which are elements? Cu C CO Co N NO WHY?
Cu C N only one kind of matter
Atomic Number Number of protons of an element
Mass Number Mass of nucleus
Mass Number Atomic Number What is the mass number of Na?
Atomic Number? Mass Number?
HOW TO FIND Number of Protons = Atomic Number
Number of Electrons = Number of Protons = Atomic Number Number of Neutrons = Mass Number - Atomic Number
How many? Protons electrons neutrons Carbon Chlorine
Is this a neutral atom? = p = e-
Same Number of electrons as protons
WHY? So the atom will be neutral (no excess charge)
What is the mass number of…?
Carbon nitrogen hydrogen WHY? Decimal number on periodic table Not other number in succession Number of p + n
What is the atomic number of?
Silicon fluorine sodium WHY? Number in succession (not a decimal) Number of protons
How do you find the number of…?
Protons electrons neutrons Atomic atomic mass no. Number number minus (if neutral) At. No.
YOU NEED TO KNOW The Names (spelled correctly) and the Symbols (written correctly) “Naturally Occurring Elements in the Human Body”
Radioisotopes All elements with atomic numbers greater than 83 are radioisotopes meaning that these elements have unstable nuclei and are radioactive and some under 83 have isotope forms.
Isotope: form of an element with a different number of neutrons
What makes atoms radioactive?
Their nuclei are unstable and they break down at a constant rate over time…and they have uneven numbers of protons and neutrons. Radioactive Decay of Uranium
Radioactive Particles Given Off
Radioactive Decay of Uranium
Number of neutrons? Isotopes? Which is the neutral form?
Which has more uneven number of protons and neutrons?
Positive Uses of Radioisotopes
Iodine-131 treat thyroid cancer Sr 89 treat bone and prostate cancer PET SCAN
Technetium-99m has become the most widely used (80%) radioisotope for diagnosing diseased organs (especially brain, heart, and bone)
Which are isotopes? 16 20 38 128 12 O F K I C 8 9 19 53 6 WHY? 38 128
O F K I C WHY? F K I different # neutrons
Formula Abbreviation for a compound
A COMPOUND is two or more elements chemically bound:
Which are formulas? Abbreviation for a compound
H2SO Cl H Al Why? H2SO H20 abbreviations for compounds (2 or more different kinds of elements)
What is a compound? 2 or more different elements chemically joined (2+ diff. capital letters) HCl H2O H2SO NOT O2
C and N only one in number
Which are atoms? C N N2 H Why? C and N only one in number
Using The Correct Term (get handout)
Element Compound Symbol Formula Atom Molecule 1 kind of Atom, Na, H 2 or more different kinds of elements chemically joined, NaCl Abbreviation of an element, H, Cl Abbreviation of a compound Na2S 1 unit of matter H Na Cl 2 or more atoms chemically joined H2, NaCl
Which are compounds? Na N H2 NO2 H2O Why? NO2 H2O
2 or more different elements chemically joined (2+ diff. capital letters)
What’s the difference? Co CO co Symbol formula nuttin
Which are molecules? Co CO CO2 O2 Why?
CO CO O2 two or more atoms (alike or not alike, it doesn’t matter) bonded together
What are the four… Most abundant elements in living matter? C H O N
What is the relative size?
Proton neutron electron 1 amu amu ~1/2000 amu AMU=atomic mass unit= 1/12 CARBON ATOM
How do electrons arrange?
In the outer shells? 2, 8, 8 Fill inner shell first, then go to next shell out
Get kinda complicated beyond 2,8,8…so that’s all we’ll do for now!
Atoms that have the same number of electrons have the same chemical properties.
How many electrons in each shell?
C O F Na 2, , , ,8,1
What are ions? Charged atoms Have lost or gained an electron
Lost or Gained How Many e-?
H+ Li+ Na+ K+ Be+2 Mg+2 Ca+2 Al+3 F- Cl- Br- I- S-2 Lost one e- Lost 2 e- Lost 3 e- Gained one e- Gained 2 e-
Note Ions and Formulas Na+ Cl- +1 -1 NaCl 1:1 Mg2+ Cl- +2 -1 MgCl2 1:2
Na+ S Na2S 2:1 Mg2+ S MgS 1:1
Which are ions? Cl O-2 Na+1 N2 Why? O-2 Na+1
Charged atoms (lost or gained electrons) show charges as superscripts
Which electrons determine…
The chemical properties of the atom? Outermost shell
Periodic Table Hint: You can tell how many electrons are in an atom’s outermost shell by just looking at its position on the periodic table!!!!!
e- in outer shells 1 2
with other atoms? Ones that do not have filled outer electron shells
Which atoms combine… with other atoms? Ones that do not have filled outer electron shells
TO HAVE FILLED OUTER ELECTRON SHELLS!!!!!!!!!!!!!!!!!!!!!!!!
What is the driving force to make atoms join with other atoms to form compounds? TO HAVE FILLED OUTER ELECTRON SHELLS!!!!!!!!!!!!!!!!!!!!!!!!
Get a filled outer electron shell?
How does an atom… Get a filled outer electron shell? Gaining, losing, or sharing electrons
If one electron is… Lost what charge will the ion have? +1
If one electron is gained…
What charge will the ion have? -1
If 2 electrons are lost… What charge will the ion have? +2
If two electrons are gained…
What charge will the ion have? -2
Making Correct Formulas:
Note how the ion charge becomes the subscript of the other ion Na+ Cl NaCl Mg2+ Cl MgCl2 Na+ S Na2S Mg2+ S MgS
What do we call the forces that…
Hold atoms together in a molecule? Chemical bonds…not to be confused with James Bond
IONIC BOND What makes up ionic bonds? IONS WHY?
Opposite charged ions attract
Covalent Bond What makes up covalent bonds?
Atoms that are sharing electrons
Comparing Bonds IONIC BOND (gain or lose e-)
COVALENT BOND (sharing e-)
How can covalent bonds be written?
Single bond double bond triple bond C-C C=C C=C C:C C::C C:::C
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