History Of The Atom And Periodic Table Flashcards
Indirect evidence
Evidence gathered without seeing or touching an object
Nucleus
The center of the atom
Subatomic particle
Particles smaller than an atom
Atomic mass unit
Special unit used to measure a subatomic particle AMU
Model
Mental picture made using the familiar ideas to explain unfamiliar facts
Groups/families
Columns going up and down grouping elements by valence electrons
Atomic number
Number of protons in an atom
Atomic mass
Average of the existing isotope
Periods
Rows across indicating the number of energy levels(ring)
Isotope
An element with matching protons but differing number of neutrons
Mass number
The most common isotope that indicates the number of protons and neutrons in the nucleus
Valence electrons
Electrons on the outer shell/ring
Oxidation number
Charge on the ion
Democritus
Philosopher asking questions
Dalton
Came up with the atomic theory(all things are made from atoms)
J.J. Thompson
Plum pudding model(positive and negative charge) and cathode tube
E. Rutherford
Gold foil experiment(positive nucleus in the center)
N. Bohr
Said that electron moved in orbit the planets
Wave model(schroedinger)
Placed electrons in electron cloud with no exact location
D. Mendeleev
Created the periodic table
Proton
Location
Mass #
Charge
Nucleus
1 AMU
Positive
Neutron
Location
Mass #
Charge
Nucleus
>1AMU
Neutral
Electron
Location
Mass #
Charge
Electron cloud
.0006AMU
Negative
First ring holds how many electrons
2
Second ring holds how many electrons?
8
Third ring hold how many electrons?
8 or 18 if number is greater than 20
How can you tell if two items are isotopes or different elements
The atomic number (number or protons) if it Is the same it is a isotope
Horizontal rows are called what?
How many are there
How are they arranged(2)
Periods
7 rows
Arranged by energy level and atomic number
Vertical columns are called what?
How many are there
How are the arranged
Groups/families
18 rows
Arranged by how many valence electrons
Why is helium a noble gas
Because noble gasses have full shells/rings and are stable
What is the purpose of the zig-zag line
To separate metals and non-metals and have metalloids touching the line
Metal
Shiny Ductile Malleable Good conductors Left side of the zig zag
Non-metals
Dull Powdery Brittle Right side of the periodic table Poor conductors
Why do atoms bond use the word noble gases
Stone bond to become stable with a full shell noble gases don’t bond because they have full shells and are stable
