Download Day 10 The Atom - WaylandHighSchoolChemistry

The Atom
Date:
• Definition of atom:
– The basic unit of an element; the
building blocks of matter
– Have no charge
– Composed of 3 subatomic particles
Energy levels:
These make up the
electron cloud
Subatomic Particles
Particle
Symbol
Charge Mass
(amu)
Location
Determines
proton
p+
+1
1
nucleus
Element
identity
neutron
no
0
1
nucleus
The
particular
isotope
electron
e-
-1
0.0005
electron
cloud
If an ion
Electrostatic repulsion and attraction
• Opposite charges attract
– Electrostatic attraction
– Protons and electrons
– Keeps the electrons from flying away
• Like charges repel
– Electrostatic repulsion
– Protons
– Why doesn’t the nucleus explode?
– The STRONG NUCLEAR FORCE
nucleons
What is the spacing within
an atom?
Numbers on the PT
What do they all mean?
Key:
Atomic number, number of protons
Element symbol
Element name
Average atomic mass
The mass calculated by summing the
masses of an element's isotopes, each
multiplied by its natural abundance on
Earth.
Nuclide
Mass number:
Sum of #p+ and # no
12
6
Atomic number:
#p+
If an atom, then #e- also
Nuclide
Mass number:
Sum of #p+ and # no
C
12
6
Atomic number:
#p+
If an atom, then #e- also
Since the atomic number is 6, there are 6 p+. This
is an atom (because there is no charge written in
the upper right hand corner) so this atom has 6 etoo! To determine the number of neutrons,
subtract the atomic number from the mass
number, 12 – 6 = 6 neutrons.
7
Li
3
Atomic # = # p+
3p+
7
Li
3
7
Li
3
3p+
3e-
No charge in upper right hand
corner, so it is an atom; the
number of p+ = # e-
Mass number – atomic number
= #no
3p+
3e4no
7
Li
-3
4
3
H
1
Atomic # = # p+
1p+
3
H
1
3
H
1
1p+
1e-
No charge in upper right hand
corner, so it is an atom; the
number of p+ = # e-
Mass number – atomic number
= #no
1p+
1e2no
3
H
1
2
14
C
6
Atomic # = # p+
6p+
14
C
6
14
C
6
6p+
6e-
No charge in upper right hand
corner, so it is an atom; the
number of p+ = # e-
Mass number – atomic number
= #no
6p+
6e8no
14
C
- 6
8
What do these all have in common?
14
C
6
13
C
6
12
C
6
• They are all C so they all have 6 p+.
But they have different mass
numbers, meaning they have
different #neutrons!
What do these all have in common?
14
C
6
13
C
6
12
C
6
These are Isotopes!
• Atoms of the same element that
differ in the # of neutrons
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Vocabulary
Atom: the basic unit of a chemical element.
Average atomic mass: The mass calculated by summing
the masses of an element's isotopes, each multiplied by its
natural abundance on Earth.
Electron: a stable subatomic particle with a charge of negative
electricity, found in all atoms and acting as the primary carrier of
electricity in solids.
Electron cloud: an atom model wherein electrons are no longer
depicted as particles moving around the nucleus in a fixed orbit
but are free to move anywhere within the cloud
Energy levels – the various levels (rings) shown around the
nucleus of an atom, the number of energy levels an atom has is
equal to the period number.
Ion – atoms with a charge because it has gained or lost electrons
Isotope – two atoms of the same element that differ in the number
of neutrons
Mass number – the sum of protons and neutron, the number of
nucleons present in the nucleus
Neutron – a subatomic particle with no charge found in the nucleus
of an atom
Nucleon – a proton or neutron
Nucleus - the positively charged central core of an atom, consisting
of protons and neutrons and containing nearly all its mass.
Nuclide - An atomic nucleus identified by its atomic element and its
mass number.
Proton – a subatomic particle with a positive charge found in the
nucleus of an atom
Strong nuclear force - one of the four basic forces in nature, this
force holds the nucleus together
Subatomic particle - a particle smaller than an atom
• Paste into notebook
• Download A+ spelling
• Type the vocabulary
term
• Enter the definitions
• Practice daily
• Until you know these
terms you will be lost
Homework
• Online quizzes
– Elements – both weeks
– Read PT
– Lab Equipment
– Safety
– Physical vs Chemical
• Vocabulary
• Worksheet on the number of
subatomic particles.