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© Boardworks Ltd 20071 of 47
2.3 Electronic
Configuration of
Elements
TB Pg 38-43
15-09-2021
WEDNESDAY
2 of 47 © Boardworks Ltd 2007
© Boardworks Ltd 20073 of 47
How are atoms arranged?
Where are the electrons found in the atom?
© Boardworks Ltd 20074 of 47
How are electrons arranged?
Electrons are not evenly spread but exist in layers called
shells. (The shells can also be called energy levels).
The arrangement of electrons in these shells is often
called the electron configuration.
Note that this diagram is not drawn to scale – the atom is
mostly empty space. If the electrons are the size shown,
the nucleus would be too small to see.
1st shell
2nd shell
3rd shell
© Boardworks Ltd 20075 of 47
Bohr’s Atomic Theory
• Electrons are in orbit around the central
nucleus of the atom.
• The electron orbits are called electron shells
(energy levels) and have different energies.
• Shells that are further from the nucleus have
higher energies.
• The shells are filled starting with one with the
lowest energy.
• The first shell can hold only two electrons.
• The second and subsequent shells can hold
eight electrons to give a stable arrangement of
electrons.
© Boardworks Ltd 20076 of 47
How many electrons per shell?
Each shell has a maximum number of electrons that it can
hold. Electrons will fill the shells nearest the nucleus first.
1st shell holdsa maximum of2 electrons
2nd shell holds
a maximum of
8 electrons
3rd shell holds
a maximum of
8 and can be
expanded to 18
electronsThis electron arrangement is written as 2,8,8.
© Boardworks Ltd 20077 of 47
Calculate electron configurations
© Boardworks Ltd 20078 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
+
1
ATOMIC NUMBER 1
GROUP 1
ELECTRONIC
CONFIGURATION
HYDROGEN
ATOMIC STRUCTURE
• atoms have the same number of electrons as protons
• electrons are found in shells (energy levels) around the nucleus
• electrons are put into the lowest energy level first
© Boardworks Ltd 20079 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
2+
2
ATOMIC NUMBER 2
GROUP 0
ELECTRONIC
CONFIGURATION
HELIUM
ATOMIC STRUCTURE
• the innermost shell can hold up to two electrons
© Boardworks Ltd 200710 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
3+
2,1
ATOMIC NUMBER 3
GROUP 1
ELECTRONIC
CONFIGURATION
LITHIUM
ATOMIC STRUCTURE
• each shell (energy level) can hold a maximum number of electrons
• the first one can only hold 2,so the next goes in the second shell
© Boardworks Ltd 200711 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
4+
2,2
ATOMIC NUMBER 4
GROUP 2
ELECTRONIC
CONFIGURATION
BERYLLIUM
ATOMIC STRUCTURE
• the second shell is gradually filled up until it has eight electrons
© Boardworks Ltd 200712 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
5+
2,3
ATOMIC NUMBER 5
GROUP 3
ELECTRONIC
CONFIGURATION
BORON
ATOMIC STRUCTURE
• the second shell is gradually filled up until it has eight electrons
© Boardworks Ltd 200713 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
6+
2,4
ATOMIC NUMBER 6
GROUP 4
ELECTRONIC
CONFIGURATION
CARBON
ATOMIC STRUCTURE
• the second shell is gradually filled up until it has eight electrons
© Boardworks Ltd 200714 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
7+
2,5
ATOMIC NUMBER 7
GROUP 5
ELECTRONIC
CONFIGURATION
NITROGEN
ATOMIC STRUCTURE
• the second shell is gradually filled up until it has eight electrons
© Boardworks Ltd 200715 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
8+
2,6
ATOMIC NUMBER 8
GROUP 6
ELECTRONIC
CONFIGURATION
OXYGEN
ATOMIC STRUCTURE
• the second shell is gradually filled up until it has eight electrons
© Boardworks Ltd 200716 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
9+
2,7
ATOMIC NUMBER 9
GROUP 7
ELECTRONIC
CONFIGURATION
FLUORINE
ATOMIC STRUCTURE
• the second shell is gradually filled up until it has eight electrons
© Boardworks Ltd 200717 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
10+
2,8
ATOMIC NUMBER 10
GROUP 0
ELECTRONIC
CONFIGURATION
NEON
ATOMIC STRUCTURE
• the second shell is now full
• full outer shells are characteristic of the unreactive NOBLE GASES
© Boardworks Ltd 200718 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
11+
2,8,1
ATOMIC NUMBER 11
GROUP 1
ELECTRONIC
CONFIGURATION
SODIUM
ATOMIC STRUCTURE
• as the second shell is full, electrons go into the third shell
• the third shell can hold up to a maximum of eight electrons
© Boardworks Ltd 200719 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
12+
2,8,2
ATOMIC NUMBER 12
GROUP 2
ELECTRONIC
CONFIGURATION
MAGNESIUM
ATOMIC STRUCTURE
© Boardworks Ltd 200720 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
13+
2,8,3
ATOMIC NUMBER 13
GROUP 3
ELECTRONIC
CONFIGURATION
ALUMINIUM
ATOMIC STRUCTURE
© Boardworks Ltd 200721 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
14+
2,8,4
ATOMIC NUMBER 14
GROUP 4
ELECTRONIC
CONFIGURATION
SILICON
ATOMIC STRUCTURE
© Boardworks Ltd 200722 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
15+
2,8,5
ATOMIC NUMBER 15
GROUP 5
ELECTRONIC
CONFIGURATION
PHOSPHORUS
ATOMIC STRUCTURE
© Boardworks Ltd 200723 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
16+
2,8,6
ATOMIC NUMBER 16
GROUP 6
ELECTRONIC
CONFIGURATION
SULPHUR (SULFUR)
ATOMIC STRUCTURE
© Boardworks Ltd 200724 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
2,8,7
ATOMIC NUMBER 17
GROUP 7
ELECTRONIC
CONFIGURATION
17+
CHLORINE
ATOMIC STRUCTURE
© Boardworks Ltd 200725 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
18+
2,8,8
ATOMIC NUMBER 18
GROUP 0
ELECTRONIC
CONFIGURATION
ARGON
ATOMIC STRUCTURE
• the third shell is now full
• full outer shells are characteristic of the unreactive NOBLE GASES
© Boardworks Ltd 200726 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
19+
2,8,8,1
ATOMIC NUMBER 19
GROUP 1
ELECTRONIC
CONFIGURATION
POTASSIUM
ATOMIC STRUCTURE
• as the third shell is full, electrons go into the fourth shell
© Boardworks Ltd 200727 of 47
H
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Ne
Ar
He
Ca
20+
2,8,8,2
ATOMIC NUMBER 20
GROUP 2
ELECTRONIC
CONFIGURATION
CALCIUM
ATOMIC STRUCTURE
© Boardworks Ltd 200728 of 47
Which element?