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The Atom: Maddy Harder Section 4 Coggle (The Atom (Dalton's Atomic…
The Atom: Maddy Harder Section 4 Coggle
Periodic Table of Elements
Periods
Horizontal Rows
Groups
Vertical Columns
Have similar chemical and physical properties
Ordered and arranged by the number of protons
in the nucleus, aka. THE ATOMIC NUMBER
Atomic Structure
In the nuclear atom, the protons and
neutrons are located in the nucleus.
The electrons are distributed around the nucleus
and occupy almost all the volume of the atom.
The Atom
Democritus
Greek Philosopher
Among the first to suggest existence of atoms
All matter has mass
Believed that atoms were indivisible and indestructible
Dalton's Atomic Theory
Atoms of the same element are identical. The atoms of any one
element are different from those of any other element.
All elements are com posed of tiny indivisible particles called atoms.
Chemical reactions occur when atoms are separated, joined, or
rearranged. Atoms of one element, however, are never changed
into atoms of another element as a result of a chemical reaction.
Atoms of different elements can physically mix together or can chemically
combine in simple whole-number ratios to form compounds.
Defintion:
What was the major contribution Democritus made to the thinking of his day?
Most Radii of Atoms fall between 5x10^-11 m and 2x10^-10 m
JJ Thomson
Particles move towards the positive charge. Attract thus they are Negative
In Cathode-Ray tube, Electrons travel as a ray from the cathode (-) to the anode (+), A television tube is a specialized type of cathode-ray tube
Charges
Positive and Negative
Determining an Atom
Atomic Number
In a neutral atom, the atomic number = the # of protons and # of
electrons.
determined by the number of protons in
the nucleus of an atom of that element.
elements are different because then
contain different numbers of protons.
Mass Number
Number of Neutrons = Mass Number - Atomic Number
The Total number of protons and neutrons in an atom
Isotopes
Examples
Neon-20
10 protons, 10 Neutrons, 10 Electrons
Neon-21
10 protons, 11 Neutrons, 10 Electrons
Neon-22
10 protons, 12 Neutrons, 10 Electrons
Atoms with the same number of protons,
but different numbers of neutrons.
Atomic Mass
Weighted average mass of the atoms in a naturally occurring
sample of the element
