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The Atom. What to look for: Three Essential Questions E. Q. #1 = What are the parts of an atom? E. Q. #2 = In what manner can subatomic particles be differentiated? E. Q. #3 = How does the atomic structure impact chemical change & reactivity?. The Building Block of Matter.
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The Atom What to look for: Three Essential Questions E. Q. #1 = What are the parts of an atom? E. Q. #2 = In what manner can subatomic particles be differentiated? E. Q. #3 = How does the atomic structure impact chemical change & reactivity?
The Building Block of Matter • 400 BC Democritus(_______ Philosopher) • Atomos = “_______________” • …like a brick is used to build a __________; an atom is used to build all matter…
First Atomic Theory • ________ (yr) John Dalton (__________ Chemist) • Using experiments formulates the first ______________ theory • All elements are composed of indivisible particles called __________ • ________ of the same elements are exactly the same • ________ of different elements are different • Two or more ______________ combine to form compounds
Subatomic Particles • The idea that the ________ was not a solid sphere, but a composition of small particles which came to be known as ______________ ________________ (2 words) • Julius Plucker, William Crooks & J J Thomson • _________________
J J Thomson • ________ Discovers the electron • First of the subatomic particles to be discovered.
Ernest Rutherford (___________Physicist) • Gold Foil Experiments • ________ Discovers that the atom is mostly empty space • Later, he discovers a hard, dense center of the atom called the ______________
The _______ is mostly empty space • Most of the _____________ passed straight through to gold foil. • First important discovery by Rutherford
The NUCLEUS is Discovered • _______ Rutherford proves that the particles that do not pass through are hitting a small, dense ______ of the atom called the nucleus. • ____________ later goes on to discover the proton
3 Name three major discoveries made by Ernest Rutherford & the Gold Foil Experiment: 1. _______________________________________ 2. _______________________________________ 3. _______________________________________ What are the two results of firing particle at atoms in the foil of the Gold Foil Experiments: 1. _______________________________________ 2. _______________________________________ 2 1 Who was the first to attempt to form a complete atomic theory? 1. _______________________________________
Electron ____________ Levels • _______ Niels Bohr (_________ physicist) discovers the electrons travel around the outside of the atom on different energy levels • The Bohr Model = “solar ___________” model
The ___________ is Found • ________ James Chadwick proves the existence of the neutron. • Only ______ years later the neutron is used to split the first atom • Why was the neutron’s existence more difficult to prove? • What evidence hinted of its existence? “the missing mass” E. Q. #1 = What are the parts of an atom?
The Subatomic Particles E. Q. #2 = in what manner can subatomic particles be differentiated?
Finding the Number of _____________ Particles in an Atom • Atomic Number = the __________ of protons in the nucleus of an atom • Identifies each element • ____________ is #1 and it has 1 proton in its nucleus (only hydrogen has 1 proton) • ____________ is #2 and it has ___ protons in its nucleus (only helium has ____ protons)
# of Electrons • IFthe atom is neutral (______ number positive charges as negative charges) then the number of electrons will be the same as protons. • ION = a charged atom (unequal number of protons and electrons) • +1 charge = the atom LOST ______ electron • -1 charge = the atom GAINED _____ electron • +2 charge = LOST _____ electrons • -2 charge = GAINED ____ electrons and so on
Example of Ions • Sodium will lose _____ electron when it bonds • Na+1 or Na+ • Sodium’s atomic number is 11, so it has 11 ________________. • The +1 charge means Na+1 has ____ electrons
Another Example • Chlorine will gain an _______ when it bonds • Cl-1 or Cl- • Chlorine’s atomic number is 17, so it has 17 ____________ • The -1 charge means Cl-1 has ____ electrons
________ Number • The _____ subatomic particles that have mass? • Proton ____ neutron, both found in the nucleus • Mass Number = # of Protons + # of Neutrons • Mass # - Atomic # = # of neutrons
Practice Problems Do Parts of the Atom & Atomic Structure practice sheet now.
ISOTOPES • Atoms of the same element with a different number of neutrons. • Ex: carbon-12 & carbon-14 • Carbon- ______ • ___ protons • ___ neutrons • ___ electrons • Carbon- ______ • ___ protons • ___ neutrons • ___ electrons
Isotopes of Hydrogen • Hydrogen-1 (protium) 0 __________ • Hydrogen-2 (deuterium) 1 __________ • Hydrogen-3 (tritium) 2 __________
The ELECTRON ______________ • The electron cloud is separated by different energy __________. • Electrons with less ________ travel on the levels closest to the nucleus. • Energy ________ are divided into sub-levels • Sub-levels are divided into orbitals • All of these _________, sub-levels & orbitals can overlap.
VALENCE ELECTRONS • Valence electrons = the outermost electrons • The ___________ involved in bonding • Determines the _________ properties of an atom E. Q. #3 = How does the atomic structure impact chemical change & reactivity? Do What Is This Atom Now? Practice sheets 1 & 2 now.
More about Electrons • Maximum # of electrons on each energy level • Level ____ = 2 electrons • Level ____ = 8 electrons • Level ____ = 18 electrons • Level ____ = 32 electrons
the Stable ______ • Due to the overlapping levels, sub-levels and orbitals the maximum number of outer most electrons is _____________. • An atom is becomes stable when it outer-most energy levels is ________ of electrons • This explains the chemical bonding properties of the _____________ • _________ will do one of three things in order to fill their outer most energy levels. • gain electrons • lose electrons • share electrons
Concepts Coming Up Next • The number of valence electrons an atom has determines the group it becomes to on the _______________ _____________. • Groups or families of elements on the periodic table has similar ______________ properties.
Concepts Coming Up Next • Valence ____________ determine how atoms will bond with other atoms in order to complete their outer-most energy level. • The Stable ______ • CHEMICAL _____________ • Ionic bonding (gaining/losing of electrons) • Covalent bonding (sharing of electrons)