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Chapter 4: Atoms and the Periodic Table
-early theory of matter
4 ingredients
1) ______; cube shaped (made it stable)
2) _____; light weight
3) ______; jagged (why it burned)
4) ______; round (allowed it to flow)
- ____- coined in the 5th century B.C. by Greek philosopher
Democritus
- means “unable to be divided”
-1800 John ______
- all matter is made of ______
- believed atoms were distinguished by their ______
- all atoms of the same element will have the same
mass
- Dalton was not concerned with the composition of
atoms, just their mass
- matter is made of different atoms
- considered the ______for modern atomic
theory
- 1897 Sir ______(J.J. Thompson)
- experiment in a ______tube
- electric current from “-“ charged electrode to “+”
electrode
- brought two electrically charged plates near tube
- beam bends towards the “___” plate
- proves beam is made of “___“ particles
- proved existence of _____
- 1914 Earnest ______- Gold Foil Experiment
1) shot ______particles at a piece of gold foil
2) foil surrounded by ______that turns florescent when
struck by an alpha particle
3) a. alpha () particle travels through foil
- proves foil is not ______
b. particles deflected and truck screen at various angles
- showed “+” alpha particles were attracted by “-“ e-
c. unexpectedly found some particles reflected _____
- repelled by “+” charge in atom
- proved existence of ______charged particle
-proton
"It was quite the most incredible event that has ever happened to me in my life. It was almost as if you fired a 15-inch shell into a piece of tissue paper and it came back and hit you." E. Rutherford
- 1932 Sir James ______
- experiment similar to Rutheford
-used ______in place of gold
- ______was given off
- found radiation weighed as much as the proton, but had
no charge
- discovered the ______
- 1913 Nels ______
- electrons in an atom move in _____ paths around the
nucleus much like the planets orbit the sun in our solar
system
- e- ______is determined by the path
- must gain or lose energy to move to different level
- 1925 modern model of atom
- electrons are more like ______on a vibrating string vs.
traveling in a definite path
- 1926 Werner ______
- exact location of an electron cannot be determined
- developed ______
- where electrons are more likely to be found
- described them in a “cloud”
- electron’s location is like blades on a fan
- individual blade location cannot be determined, but
area of likelihood can be
- number of filled levels depends on the number of e-
1st energy level ___e-
2nd energy level ___e-
3rd energy level ___e-
4th energy level ___e-
- clouds are made of ______
4 types of orbitals
1) ____ orbital
- single orientation
- sphere shaped
- lowest energy
- holds ___ electrons
2) ____ orbital
- dumbbell shaped
- 3 orientations (x,y,z)
- each of the three p orbitals can hold ___ electrons
- holds ___ electrons total
3) ____ orbital
- 5 orientations
- each holds ____ electrons
- holds ___ electrons total
4) ___ orbital
- 7 orientations
- each holds ____ electrons
- holds ___ electrons total
- ______- electrons in the outermost energy level
- determine chemical ______and
______
- Ex.- hydrogen vs. neon
- hydrogen has 1 e-
- 1 valence electron
- neon has 10 e-
- 2 in the first energy level
- 8 in outer (valence) energy level
Periodic Table
- groups similar elements together
- allows for ______
- order is based on number of ______
- ______- when elements are arranged by proton
number, similarities in their properties
occur in patterns
- lots of different arrangements over time
- Dmitri Mendeleev 1896
- arranged by ______
- left spaces where needed
- correctly ______properties of several of the
empty spaces
- Henry ______rearranged table based on increasing
number of protons
- took care of a few discrepancies in
Mendeleev’s table
- ______- horizontal rows on periodic table
- set up several ______including electron
arrangement
- Ex.- Hydrogen
- 1 electron
- electron is in 1st energy level
- Ex.- Nitrogen
- 7 electrons
- 1st energy level, s orbital 2e-
- 2nd energy level, s orbital 2e-, p orbital 3e-
2e- + 2e- + 3e- = 7e-
- ______or ______- elements in horizontal columns
- same number of valence electrons
- similar properties
- ___- an atom that has gained or lost one or more electrons
- has a “+” charge if an electron is lost (______)
- has a “-“ charge if an electron is gained (______)
- Ex.- Lithium 3e-
- 2 in 1st energy level, 1 valence electrons
- loses e-….. Li+
- Ex.- Fluorine 9e-
- 2 in 1st energy level, 7 in second energy level
- gain an electron…..F+
***electron configuration determines properties***
- ______- (z)
- number of ______
- number of ______when atom is neutral
- never changes for a given element
- ______- (a)
- number of protons and neutrons
- do not include e- because they are so small
- to get the number of ______, subtract the
atomic ______from the atomic ______
A – Z = number of neutrons
- ______- atoms of the same element may
have different mass numbers
- not all are stable
- Ex.- Carbon-12, Carbon-13, Carbon-14
98% 1.12% trace
6 protons 6 protons 6 protons
6 neutrons 7 neutrons 8 neutrons
- isotope notation
2 forms
1) symbol followed by ______
- Ex.- Cl-35
2) symbol with mass and atomic number on left side
- mass of an atom is very small
- fluorine’s mass is less than one trillionth of a billionth
of a gram
- ______- (amu)
- used in place of ______
- equal to 1/12 the mass of carbon-12 atom
- proton and neutron mass is equal to one amu
- ______- weighted average
- used on periodic table
- more common isotope has a larger
effect than rarer isotope
Classifying Elements (3 classifications)
1) ______- an element that is shiny (luster) and conducts
heat and electricity well, also malleable
2) ______- right side of periodic table (except
hydrogen)
3) ______
- considered non-metals
- may conduct electricity
Metals (4 types)
1) Alkali Metals/ group _____
- far ______column on periodic table
- soft, shiny, reacts violently with water
- not found in nature as ______
- too reactive
- form compounds
2) Alkaline-earth Metals/ group ______
- _____ column from left on periodic table
- 2 valence electrons
- less reactive than alkali metals
- form +2 ions
- Ex.- Calcium
- shells of many sea creatures
- make limestone and marble; coral reef
- bones and teeth
- Ex.- Magnesium
- lightest of all structural metals (airplanes)
- enzymes in body
3) Transition Metals/ groups ______
- much less reactive than groups ____ and ____
- form “+” ions
- many form several possible ions
- good conductors of heat and electricity
- ______(stretched and shaped)
- good for jewelry (shiny)
4) ______Elements
- man made
- radioactive (always decaying)
- make different elements
- technetium, promethium, and any element with an
atomic number greater than 92
- many make up two rows at bottom of periodic table
- allows table to be thin and still have other families
line up
Non-Metals
- right side of periodic table
- groups 17,18 and some elements in groups 13-16
- must form “-“ ions
- Carbon
- 3 forms
1) ______
2) ______
3) ______
- found in living and non-living things
- oxygen, nitrogen, sulfur
- form “-“ ion
- halogens/ group ______
- 2nd column from right
- very reactive
- form “-“ ions
- uses
- Chlorine
- Cl gas is very deadly
- table salt ______
- Fluorine
- poisonous yellow gas
- fluoride in ______
- Bromine
- dark red liquid
- Iodine
- dark purple solid
- needed for ______
- Noble gases/ group ______
- column furthest on the right
- exist as single atoms only
- inert/unreactive
- do not gain or lose electrons
- do not form compounds under normal conditions
Semi-conductors/metalloids
- 6 elements
1) ______
- hard element
- added to steel for strength
- heat resistant glass
2) ______
- makes up 28% of the Earth’s crust (sand)
- computer chips
3) ______
4) ______
- shiny solid that tarnishes in air
5) ______
- bluish white solid
- shines like metal
- fire retardants
6) ______
- shiny white solid
- classified as non-metals, but have some properties of
metals
- Ex.- may conduct heat and electricity under certain
conditions
Counting
- ______- (mol)
- counting unit
- defined as the number of atoms in 12.00 grams of
carbon-12
- ______constant- 6.02 x 10 23
(602,213,670,000,000,000,000,000)
- number of particles in exactly 1 mol of a ______
substance
- Ex.- 1 mole of popcorn is 6.02 x 1023kernels
- cover U.S. and be 500 km high
- ______- mass in grams of 1 mol of a substance
- for elements, the molar mass equals its
average atomic mass in amu
Calculations
10 gumballs = 21.4 g
50 gumballs = ?
50 gumballs x 21.4 g . = 107 g
10 gumballs
- can do the same thing with elements
- amount of elements (avagadro’s number)
- mass in grams (mass number)
- Ex.- mass of 5.5 mol of iron
1) look up mass of iron (Fe) on periodic table
Fe = 55.85
5.5 mol Fe x 55.85 g Fe = 307 g Fe
1 mol Fe