Chapter 4 (Periodic Table Of Elements (Periods (Horizontal rows ), Groups…
Periodic Table Of Elements
Have similar chemical and physical properties. ordered and arranged by the number of protons in the nucleus aka the atomic number
Weighted average mass of the atoms in a naturally occurring
sample of the element
Dalton's atomic theory
Atoms of different elements can physically mix together or can chemically
combine in simple whole-number ratios to form compounds.All elements are composed of tiny invisible particals called atoms. Atoms of the same element are identical. The atoms of any one
element are different from those of any other element. 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.
Number of protons determines the atomic number of an atom.
Discovered in 1886 Eugen Goldstein
Large Particle (1840x the mass of electron.)
Neutral charge Discovered in 1932 James Chadwick Mass equal to the proton
Smallest part of the Atom Discovered in 1897 Physicist J. J. Thomson Negatively Charged
Believed that atoms were indivisible and indestructible.Greek Philosopher. Among the first to suggest existence of atoms.
Atoms with the same number of protons,
but different numbers of neutrons. 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
the Total number of protons and neutrons in an atom. Number of Neutrons = Mass Number - Atomic Number
determined by the number of protons in
the nucleus of an atom of that element. In a neutral atom, the atomic number = the # of protons and # of
Most Radii of Atoms fall between 5x10^-11 m and 2x10^-10 m
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.