Unit 3- Atomic Structure And Theory

Front 1

Charge of Atomic Particles

Back 1

Electron: -1
Proton: +1
Neutron: 0

Front 2

Atomic Number (3 details) = Z

Back 2

-The number of protons in the nucleus of an atom
-The number of protons defines an element (change in proton number makes a new element)
-Atomic Number = Number of Electrons in neutral atom

Front 3

Mass Number = A

Back 3

The number of protons and neutrons in the nucleus of an atom (if not given, it equals the atomic mass)

Front 4

Isotope

Back 4

Variations of atoms/elements with the same number of protons but different neutrons

Front 5

Isotope Symbol and Symbolic Notation

Back 5

1.
Mass # over Atomic # -> Element

2.
X-Mass #

Front 6

Different # of Neutrons...
Different # of Protons...
Different # of Electrons...

Back 6

... diff. # of neutrons - Isotope
... diff. # of protons - Element
... diff. # of electrons - Ion

Front 7

Atom

Back 7

The smallest particle of an element that retains the properties of that element

Front 8

AMU

Back 8

-amu - Atomic Mass Unit
-based on C-12
-1 amu is 1/12 the mass of C-12

Front 9

Atomic Mass

Back 9

The weighted average mass of the isotopes of that element

Ex.
75% Cl-35
25% Cl-37

(.75)(35)+(.25)(37)= 35.543 amu

Front 10

Nucleons

Back 10

The particles found in the nucleus of an atom, protons and neutrons

Front 11

Radioactive (3 details)

Back 11

-Nucleus which spontaneously decomposes forming a new nucleus and producing one or more particles
-An atom of one element changing into the atom of another element
-Atoms that are unstable become stable by losing energy in the form of radiation

Front 12

Nuclear Equation

Back 12

Equation that shows the radioactive decomposition of an element

Ex. C-14 -> N-14 + e-0

Front 13

Alpha Radiation - 4/2He

Back 13

-Helium nucleus
-2 protons and 2 neutrons
-Charge of +2
-Symbol α
-Deflected towards negatively charged plate
-Blocked by paper

Front 14

Beta Radiation - 0/-1e

Back 14

-Charge of -1
-Deflected towards a positively charged plate
-Blocked by foil
-Symbol β

Front 15

Gamma Radiation

Back 15

-No mass
-High energy photon
-No charge
-Blocked by concrete, lead and water
-Symbol γ

Front 16

Nuclear Fission

Back 16

Splitting of atoms into fragments, releases lots of energy, chain reaction occurs, produces radioactive waste and used to produce power in nuclear reactors

Front 17

Nuclear Fusion

Back 17

Combining of nuclei, releases lots of energy, not radioactive and takes place in the Sun

Front 18

Half-Life

Back 18

Time required for half of the original sample of radioactive nuclides to decay

Ex. 100 g of substance w/ 5 year half-life

0 days - 100 g left
5 days - 50 g left
10 days - 25 g left
15 days - 12.5 g left

Front 19

John Dalton

Back 19

1803, proposed Atomic Theory based on atoms of elements having different weights

6 main points:
-All matter has atoms
-Atoms can not be made or destroyed
-All atoms of same element are identical
-Diff. elements = Diff. atoms
-Chem. reactions occur when atoms are rearranged
-Compounds formed from atoms that make up elements

Front 20

JJ Thomson

Back 20

-1897, discovered the electron through electric discharge experiments
-Atom is sphere of positive matter
-1913, discovered isotope

Front 21

Ernest Rutherford

Back 21

-1911, theory of central positive nucleus surrounded by negative orbiting electrons
-Most of atom mass in nucleus
-"Gold foil experiment"

Front 22

James Chadwick

Back 22

-1932, discovered the neutron

Front 23

Speed of Light Formula

Back 23

Speed of light = Wvlngth * Freq
3*10^8 = lambda (y) * nu (v)