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Science PresentationJesse and DiannaATOM MODELModel Of The AtomAtoms are composed of:Positively Charged ProtonsNegatively Charged ElectronsNeutrons with no chargeElectrons are arranged in orbits called energy levels, or shells aroundthe nucleus

Energy levelsEnergy levels are arranged based on their distance from the nucleus of the atom.The first energy level can hold 2 electrons, the second can hold 8, and the third can also hold 8Valence electrons refer to the number of electrons that an atoms outer most shell containsAtoms with the maximum amount of valence electrons in their outer most shell are more stable because they tend not to gain or lose electrons

Atom model QuestionsHow many electrons can the 2nd energy level hold within an atom?

Which atom is more stable, Neon (with an atomic number of 10) or Magnesium (with an atomic number of 12)?

How many valence electrons does silicon (atomic number 14) have?

AnswersHow many electrons can the 2nd energy level hold within an atom? 8 Electrons

Which atom is more stable, Neon (with an atomic number of 10) or Magnesium (with an atomic number of 12)? Neon, because its outer most shell of electrons is full.

How many valence electrons does silicon (atomic number 14) have? 4 valence electrons because the first two energy levels contain the first 10 electrons.PERIODIC TABLEThe periodic table is organized into periods and families.

The periodic table is organized into periods and families.

iA2A3A4A5A6A7A8A9A10A11A12A13A14A15A16A17A18AEach box in the periodic table represents an element.

2A3A4A5A6A7A8A9A10A11A12A13A14A15A16A17A18A

Each box in the periodic table represents an element.

ATOMIC SYMBOL

Each box in the periodic table represents an element.

ATOMIC NUMBEREach box in the periodic table represents an element.

ATOMIC MASSNUMBERElements in the same period have the same number of energy levels.

2A3A4A5A6A7A8A9A10A11A12A13A14A15A16A17A18A

Elements in the same family have the same number of valenceElectrons and similar properties.

2A3A4A5A6A7A8A9A10A11A12A13A14A15A16A17A18A

REVIEW QUESTIONSYou should be looking at a periodic table for this.http://ptable.com is a good one.What element is in period 2 and group 13A?BORON

2A3A4A5A6A7A8A9A10A11A12A13A14A15A16A17A18AI am a halogen with 7 valence electrons and an atomic mass of about 127 amu.What am I?(Use ptable.com for this one.)IODINE

2A3A4A5A6A7A8A9A10A11A12A13A14A15A16A17A18AAVERAGE ATOMIC MASSElements have isotopes: forms of an element with different numbers of neutrons, but the same number of protons and electrons.

22Isotopes of an element will be represented like this:

235U235UElementAtomic MassFINDING AVG. ATOMIC MASSJ1= atomic mass of isotope 1J2= atomic mass of isotope 2A1= abundance (%) of isotope 1A2= abundance (%) of isotope 2

Avg. Atomic Mass = J1 A1 + J2 A2Abundance = how often the isotope occurs in natureREVIEW QUESTIONSRubidium has two common isotopes: 85Rb (72.2%) and 87Rb (27.8%).

What is the average atomic mass of rubidium?

(hint: use the formula)

J1= 85 amuJ2= 87 amuA1= 72.2%A2= 27.8%

Avg. Atomic Mass = 85 0.722 + 87 0.278 85.56 amuCopper has two isotopes: 63Cu (69.09%) and 65Cu (30.91%).

What is the average atomic mass of copper?

J1= 63 amuJ2= 65 amuA1= 69.09%A2= 30.91%

Avg. Atomic Mass = 63 0.6909 + 65 0.3091 63.62 amuWhy is the mass in amu of a carbon-12 atom reported as 12.011 in the periodic table of the elements?The masses on the periodic table are the average mass of all isotopes and their abundances found in the universe. Although carbon-12 weighs exactly 12 amu, the periodic table reports that the mass is 12.011 because we are taking into consideration the abundances and masses of the other two carbon isotopes (carbon-13 and carbon-14)