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Regents review: topic 1 – the atom. DO NOW: Take out HW 2. In M.C. Packet COMPLETE MULTIPLE CHOICE QUESTIONS pg. 6-8 all Atomic Structure questions. REGENTS REVIEW TOPIC 1 – THE ATOM.
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Regents review: topic 1 – the atom DO NOW: Take out HW 2. In M.C. Packet COMPLETE MULTIPLE CHOICE QUESTIONS pg. 6-8 all Atomic Structure questions
REGENTS REVIEW TOPIC 1 – THE ATOM • Modern model of the atom has evolved over a long period of time through the work of many scientists • Dalton: (hard sphere) • Elements are made of atoms • Atoms of an elements are the same • Compounds are formed from a combination of atoms
REGENTS REVIEW TOPIC 1 – THE ATOM • Thomson • Plum Pudding Model • Rutherford Experiment • Bombard gold foil with alpha particles • Atoms are mostly empty space With small dense positively charged nucleus
REGENTS REVIEW TOPIC 1 – THE ATOM • Bohr Model: • Small dense positively charged nucleus surrounded by electrons in circular orbit • Wave Mechanical Model • Small dense positively charged nucleus surrounded by an electron cloud • “Orbitals” – areas where an electron with a certain amount of energy is most likely to be found
REGENTS REVIEW TOPIC 1 – THE ATOM • Each atom is made of a positively charged nucleus with one or more negatively charged electrons • Protons and neutrons are found in the nucleus • Protons have a positive charge • Neutrons have a neutral charge • Electrons have a negativecharge
REGENTS REVIEW TOPIC 1 – THE ATOM • # of protons = # of electrons - atom is neutral • Mass of proton - 1 amu • Mass of neutron – 1 amu • Mass of electron – negligible mass • Atomic mass of an atom = # protons + # neutrons • amuis = 1/12 mass of carbonatom
REGENTS REVIEW TOPIC 1 – THE ATOM • Each electron in an atom has its own distinct amount of energy • All electrons in lowest energy = ground state • Electrons fill in energy levels and orbitals that requires the least amount of energy and then move up to the next energy level • Electrons gain energy and move to higher orbitals – excited state • Electrons return from higher energy state to a lower energy state • Emits energy in the form of light • Bright line spectrum
REGENTS REVIEW TOPIC 1 – THE ATOM • Outermost electrons – valence electrons • Responsible for chemical properties • Most elements max # of valence electrons = 8 (except H which only has 2) • Atoms form bondsto fill their valence shell • Can use orbital notation or Lewis Dot Sructureto show the configuration of the valence electrons • Atoms of the same element all contain the same number of protons • Changing the number of protons changes the atom into a different element • The atomic number = # of protons of an element
REGENTS REVIEW TOPIC 1 – THE ATOM • Isotopes are atoms with equal numbers of protons but different number of neutrons • Isotopes of an element have the same atomic number but different atomic masses • The average atomic mass of an element is the weighted average of its naturally occurring isotopes • The formula for calculating the average atomic mass is:
CONCLUSION • COMPLETE # 1-16 PG. 2 OF HANDOUT