1 k 0106f_particles of matter
-
Upload
max-zara -
Category
Technology
-
view
1.173 -
download
0
Transcript of 1 k 0106f_particles of matter
Rutherford and the nucleus
British physicist who, in 1911, proved that atoms had a small, dense, positively charged nucleus.
Rutherford’s Model Protons ( the positively charged sub-
atomic particles ) are concentrated in a small area at the center of the atom.
He called this area the nucleus. An atom is mostly empty space. The nucleus is tiny compared to the
whole atom, but it contains nearly all the atom’s mass.
1
Rutherford’s Model of the Atom
Limitation: did not specify exactly where the electrons were
2
Bohr and energy levels
Danish scientist who, in 1913, proposed the “Planetary Model” of the atom
The energy levels occupied by electrons are like the orbits of planet at different distances from the sun.
Bohr compares electrons to the planets and nucleus to the sun.
3
In 1932, James Chadwick discovered the neutron.
The nucleus contains neutrons. A neutron has about the same
mass as a proton but has no electrical charge.
Jimmy neutron walked into a bar and asked how much for a drink. The bartender replied, "for you, no charge."
-Jaime - Internet Chemistry Jokes
Chadwick and the neutron4
Quantum Mechanical or Electron Cloud Model
Electrons dart about within an energy level in an ever – changing path.
Their rapid motion creates a “ cloud” of negative electricity around the nucleus.
The electron cloud gives an atom its size and shape.
5
Electron Cloud Model
n nucleus
electron cloud
6
Seatwork:
In size 4: start identifying the 5 suspects
In your SBP, draw the models of Dalton, Thomson, Rutherford, Bohr and the Quantum model. Label and write a short description about the model.
7
Let us see if you got it right.
1. Dalton 2. Rutherford 3. Thomson
4. Bohr 5. Democritus
8
Atomic Models
Dalton’s Atomic Model
Rutherford’s Atomic ModelThomson’s Atomic
Model
Electron Cloud Model
Bohr’s Planetary Atomic Model
9
A CLOSER LOOK ON ATOMS
10
11
12
13
ATOMS
Potential energy and kinetic energy are present in the atom
Atoms are always neutral in charge In an atom, no. of protons = no. of
electrons Atomic number:
Lower in amount than mass number Number of protons in an atom Tells you the identity of the element
Mass number/ Atomic weight/Atomic mass: Higher in amount than atomic munber Number of protons and neutrons in an
atom
14
Computation in atoms
# of protons = Atomic number # of electrons = Atomic number # of neutrons = Mass number– Atomic
number Mass number = # of protons + # of neutrons
15
Element
Mass Number
Atomic Number
Number of
Protons
Number of
Electrons
Number of
Neutrons
Li
Cu
Cl
Ag
Pb
16