Defining the Atom faith deVlaminck section 4 coggle (atomic structure …
Defining the Atom faith deVlaminck section 4 coggle
Among the first to suggest existence of atoms.
Believed that atoms were indivisible and indestructible.
Dalton atomic theory
All elements are com posed of tiny indivisible particles called atoms.
Atoms of the same element are identical. The atoms of any one
element are different from those of any other element.
Atoms of different elements can physically mix together or can chemically
combine in simple whole-number ratios to form compounds.
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.
The smallest particle of an element that
retains its identity in a chemical reaction.
Most Radii of Atoms fall between 5x10^-11 m and 2x10^-10 m
Periodic Table of Elements
Ordered and arranged by the number of protons
in the nucleus, aka. THE ATOMIC NUMBER
Have similar chemical and physical properties.
Discovered in 1932
Mass equal to the proton
Discovered in 1897
Physicist J. J. Thomson
Smallest part of the Atom
The electrons are distributed around the nucleus
and occupy almost all the volume of the atom.
In the nuclear atom, the protons and
neutrons are located in the nucleus.
Large Particle (1840x the mass of electron.)
Discovered in 1886
Number of protons determines the atomic number of an atom.
Each element will have a different number of protons in its nucleus.
Oxygen – 8 protons
Hydrogen – 1 proton
Uranium – 92 protons
Helium – 2 protons
Boron – 5 protons
Silver – 47 protons
What is an atomic number?
the number of protons in the elements nucleus.
What is the mass number?
the total number of protons and neutrons in an atom.
How do you determine an elements mass number?
look at an elements average atomic mass, and round it to the nearest whole number.
Helium – Average Atomic Mass = 4.0026 Mass Number = 4
Gold - Average Atomic Mass = 196.97 Mass Number = 197
Key Concept #2 Answer: The number of neutrons in an atom is the difference between the mass
number and atomic number.
the four parts of Dalton's atomic theory
1) All matter is made of atoms. Atoms are indivisible and indestructible.
2) All atoms of a given element are identical in mass and properties
3) Compounds are formed by a combination of two or more different kinds of atoms.
4) A chemical reaction is a rearrangement of atoms.
determining an atom
Weighted average mass of the atoms in a naturally occurring
sample of the element
elements are different because then
contain different numbers of protons.
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
the Total number of protons and neutrons in an atom.
Number of Neutrons = Mass Number - Atomic Number
10 protons, 11 Neutrons, 10 Electrons
10 protons, 12 Neutrons, 10 Electrons
10 protons, 10 Neutrons, 10 Electrons
Discovered in 1897 by English physicist J.J.Thompson.
Electrons are negatively charged subatomic particles.
Discovered in 1932 by English physicist James Chadwick.
Neutrons are subatomic particles that do not carry a charge. They are neutral.
The mass of a neutron is nearly equal to a proton.
Discovered in 1886 by Eugen Goldstein.
Protons are positively charged subatomic particles.
A proton has a mass about 1840 times that of an electron.
What is an atom?
is the smallest particle of an element that retains its identity in a
It is also considered the building blocks of all matter.
Who was Democritus? What did he do? When was he alive?
Democritus was a Greek philosopher.
He was one of the first to suggest the existence of atoms.
460 B.C. – 370 B.C.
What is a nucleus?
Tiny central core of an atom and is composed of protons and neutrons.
What is an electron cloud?
Region surrounding the nucleus where an electron most likely will be found.
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.