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Unit 3: Counting atoms. Subatomic Particles. Proton. Determines the element Number of protons CANNOT change for an element Common charge notation is +1 Mass (g) = 1.673 x 10 -24 Mass ( amu )= 1.0073 = 1. Neutron. Common charge notation is 0. No charge!
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Proton • Determines the element • Number of protons CANNOT change for an element • Common charge notation is +1 • Mass (g) = 1.673 x 10-24 • Mass (amu)= 1.0073 = 1
Neutron • Common charge notation is 0. No charge! • Mass (g) 1.675 x 10-24 (same mass as proton) • Mass (amu)= 1.0082 = 1 • Number of neutrons CAN change for an element • ISOTOPES • Stabilizes nucleus by nuclear force
Electron • Common Charge notation is -1 • Mass (g) of e- = 9.109 x 10-28 • Mass (amu)= .0006 = 0 • Number of electrons CAN change for an element • IONS • Responsible for chemical reactivity, forms bonds
Check your understanding • Which subatomic particle can NOT change for an element and gives it’s identity? • Which subatomic particle stabilizes the nucleus?
Section 3: Counting Atoms • Atomic Number: The number of protons in each atom of that element. • Unique to EACH element, never changes!! • Neutral atoms: proton #= electron # • Example: • How many protons does Beryllium (Be) have? How many electrons? • How many protons does Gold (Au) have?
Isotope • Isotopes: Are atoms that have different number of neutrons • So masses are different Example of isotopes:
Mass number • Mass Number: The total number of protons and neutrons in the nucleus
Hyphen notation • Element- Mass number • What is the hyphen notation of lithium if the mass number is 4?
Common isotopes of carbon Carbon-12 Carbon-13 Carbon-14 How many protons do all the carbon isotopes have? How many neutrons do each of the carbon isotopes have?
APE MAN • Atomic #= Proton #= Electron # (because we assume atoms are neutral) • Mass #= Atomic # + Neutron #
APE MAN • # protons= Atomic number • # electrons = # of protons (in a neutral atom) • # neutrons = Mass #– Atomic number #
Atoms • Atoms are Neutral because they have the same number of electrons and protons • You will assume this unless indicated otherwise
Ions • Ions :are when the electron number and proton number are different leading to a net charge. • NOTE: YOU WILL ALWAYS ASSUME ATOMS ARE NEUTRAL (protons = electrons) UNLESS TOLD OTHERWISE
Average Atomic Mass • Average atomic mass is the weighted average of the atomic masses of the naturally occurring isotopes • DO NOT look at this number when trying to find mass #.
“BlUFF” RULES • You must answer the question by yourself • When you have it, write it down on a piece of paper • Bring the worksheet you picked up in the back • Winning team gets 5 points • Don’t single one person out on the other team each time.