SCIENCE STUDY!!!!!

Atomic#

Atomic#

Atomic # (A#) = # of protons(p+) in the nucleus

Identifies the element

Mass #

Mass # = total # of protons(p+) + neutrons(n0)

# of neutrons

(n0) = Mass # - Atomic #

Dalton’s atomic theory

1. All elements are composed of tiny indivisible particles called atoms
2. Atoms of the same elements are identical-false!

3. Atoms of different elements can physically mix together or combine in simple whole # ratios to form compounds
4. Chemical reactions occur when atoms separate, join or rearrange

J. J. Thomson

Discovered electrons - cathode ray

Robert Millikan

Mass of electron - Oil drop experiment (mass = 5.4 x 10-4 of H)

Ernest Rutherford

Nucleus and Protons- Gold Foil Experiment

James Chadwick

Neutron

Alpha Particle

Lowest Penetration (0.05 mm)

Symbol=He or α

Mass = 4

charge = +2

Paper/clothes

Beta Particle

Moderate

4 mm body tissue

symbol = β

Mass = 0

charge = -1

Shielding – metal foil

Gamma particle

very high

symbol = γ

mass and charge is 0

Shielding – lead, concrete

Half-Life Calculation

(t1/2)
Time required for half of the original amount to decay

Nuclear Equation

Conservation of Mass
– Mass number of reactants MUST equal the
mass number of product (top)
– Atomic number of reactant MUST equal the
atomic number of product (bottom)

Dalton model of atom

solid invisible mass

J.J. Thomson model of atom

“Plum-pudding” model

Ernest Rutherford model of atom

e- surrounding a dense nucleus

Niels Bohr model of atom

e- traveling in circular paths called “orbits”(energy levels)

Erwin Schrödinger model of atom

“Quantum Mechanical” model

Quantum numbers

Describes the location of any electrons

Principal of quantum numbers

energy level (distance from the nucleus) (n = 1, 2, 3, ...)

Orbital of quantum numbers

shape of orbitals (s, p, d, f) (region of space of finding e-)

Electron Configuration

Arrangement of electron

Aufbau principle

e- enters the lowest energy level 1st
• 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

Pauli exclusion principle

an atomic orbital may describe at most 2e- (NO 2e- may have the same Q#) (e- may either spin up or down)

Hund’s rule

when e- occupy orbitals of equal
energy, 1e- enter each orbital until all the orbitals
contain 1e- w/parallel spin

Order of filling the orbitals

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

Short-hand electron notation

Use group 18 (8A) (Noble gases) as the starting point. Noble gas MUST be 1 row above the element.

orbital notation

Use arrows for electron, and use lines to show the different kind.

Wavelength

distance from one peak to another peak

frequency

# of peaks per second (Hertz)

Lithium Flame Test

Red

Sodium Flame Test

yellow/orange

Potassium Flame Test

Lavender

Calcium Flame Test

Orange/red

Copper Flame Test

Green

Periodic Table 1st one

Mendeleev– Published the 1st table with elements arranged in similarities of their properties
• Increasing atomic weight

Revised periodic table

Henry Moseley-Rearrange the table in increasing A#

Periodic horizontal rows

7

Group – vertical columns

18

Representative groups

group a

Transition metals

group b G3 to G12

Inner transition metals

bottom 2 rows

Alkali metal

(G1 or G1A, except H) *very reactive

Alkaline earth metal

(G2 or G2A) *reactive

Halogen non-metal

(G17 or G7A)

Noble gas-where it is

(G18 or G8A) *Non-metal, gas, non- reactive

Ductile, malleable, shiny, solid, strong,
conducts heat and electricity

Metals

Most of the periodic table
– On the left side of the metalloids

Solid to gas, brittle, Does not conduct heat or
electricity

Non-metal

Metalloid

Semi-conductors, solid, separates metal from non-
metals – B, Si, Ge, As, Sb, Te and
At

Noble gas

completely filled s & p orbital (Except He – only filled s)

Representative

partially filled s or p orbital (Groups 1,2 and 13-18)

Transition

filled s and partially filled d orbitals (Groups 3-12)

Inner transition

filled s, d1 and partially filled f orbitals

Atomic radius Trend

½ the distance between nuclei of 2 like
atoms
• Group = bigger as ↓(go down) the group
• Period = smaller as →(go to the right) the period

Ionization energy def

Energy required to remove 1 e- from a neutral atoms

IE trend

Group = smaller as ↓ the group (bigger size, less attraction,
easier to remove e-, less IE)
• Period = bigger as → the period (smaller size, more
attraction, harder to remove e-, more IE)

Electronegativity Trend

Tendency of an atom to attract an e-
• Same trend as I. E

Amplitude

the maximum distance the particles of the medium move from their resting positions when a wave passes through.

Ground state

the lowest energy state of an atom or other particle.

Photon

a tiny particle that comprises waves of electromagnetic radiation.

Spectrum

Wavelength of light that is separated into color when passed through a prism

Quantum Def

energy required to move from a lower energy level to a higher one

Atomic Mass def

weighted average mass of the atom in a naturally occurring sample

Nuclear Force

energy that holds neutrons and protons together in the nucleus

Radiation

penetrating rays & particles emitted during radioactivity