Atomic Structure and Electron
Arrangement
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Write correct symbols and names of some elements
Describe the physical properties of some elements
Categorize an element as a metal or non-metal from its physical properties
Describe the color of a flame produced by an element
Draw a model of an atom including the electron arrangement for the first
20 elements
The Atom
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All matter on Earth is made from atoms
Atoms are really tiny less than a billionth of a meter across
Only been imaged in recent decades
Too small to see with visible light
The Atom
• The atom is made up of 3 subatomic
particles
• The Proton
• The Electron
• The Neutron
• The atom has a nucleus (made up of
protons and neutrons)
• The electrons exist as waves in a
cloud around the nucleus
The Atom
The Elements
• There are 98 naturally occurring elements, (the first 98)
• These are listed according to their atomic number Z
• Each element with a different atomic number is denoted by a Chemical
Symbol – a one or two letter symbol – often Greek or Latin in origin and
sometimes good ol’ English (C = Carbon, Si = Silicon, Br = Bromine etc)
• The elements are listed in a table, ordered in increasing atomic Number as
one goes across and down the periodic table
• Elements in a given column share certain chemical properties that make
them similar
Elements: Patterns and the Periodic Table
Elements: Patterns and the Periodic Table
Part A: The Elements
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In Part A you will be becoming familiar with writing the Chemical symbol,
atomic number and physical properties for selected elements
The elements are defined by how many protons are in the nucleus
We call this the Atomic Number Z
Examples
– Helium has 2 protons
– Hydrogen has 1 proton
– Aluminum has 13 protons
Part B: The Elements
• In Part B – use the empty periodic table to
– Write the atomic number and symbol for the
elements identified in part A
– Write the group number at the top of each column
– Write out the period numbers for each horizontal row
– Use different colors to highlight, alkali metals, alkaline
earths, halogens, noble gases and transition metals
– Draw a heavy line to separate metals from non-metals
Part C: Subatomic Particles
• In part C we look at the subatomic particles that
make up atoms
• Atomic number Z = # protons = p+ = # electrons = e• Z defines what element we have
• Mass Number = # of protons + # of neutrons =p+ + n0
Element
Atomic
Number
Mass
Number
Protons
Neutrons
Electrons
Iron
26
26+30=56
26
30
26
27
13
14
13
Aluminum 27-13=14
Part D: Isotopes
Mass number = p+ + n0
34
Atomic Number Z = p+
16
Nuclear Symbol Protons
40
20
Ca
20
S
Symbol of the Element
Neutrons
Electrons
40-20 = 20
20
Part E: Flame Tests
• When heats electrons in atoms and ions can be excited to higher
energy levels
• When they cool down the electrons return to their ground state
and release energy as light
• Group 1A and 2A elements produce colorful flames
• The color of the flame is like a fingerprint for that element/ion
• Discover the color of flames containing CaCl2, KCl, SrCl2, BaCl2, CuCl2
and NaCl
• Identify ions in the mystery solutions
Part F: Drawing Models of Atoms
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The shape of the periodic table is connected to how the electrons are structured in
the atom
Electrons behave as waves sloshing back-and-forth
The different waves are called a orbitals
There are s, p, d, and f orbitals, s orbitals can fit 2e-, p 6e-, d 10e- and f 14eThe higher the energy of the electron the further it is from the nucleus on average
Row in Periodic
Table
Number of
electrons
Orbitals involved
1
2
1s
2
8
2s,2p
3
18
3s,3p,3d
Part F: Drawing Models of Atoms
• In Part F you will be asked to draw out a simplified electronic structure for
certain elements in the following way
• First Row Atom 24 He
40
• Fourth Row Atom 20
Ca