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CHAPTER 6
Elements and the Periodic
Table
6.2 Properties of Groups of Elements
2 6.2 Properties of Groups of Elements
There are millions and millions of different kinds of matter (compounds) composed of the same 92 elements.
These elements are organized in a periodic table.
It is called “periodic” because there is a repeating pattern.
3 6.2 Properties of Groups of Elements
There are millions and millions of different kinds of matter (compounds) composed of the same 92 elements.
These elements are organized in a periodic table.
It is called “periodic” because there is a repeating pattern.
Elements that belong to the same column have similar chemical properties.
Here, we are going to go over these groups of elements
4 6.2 Properties of Groups of Elements
Alkali metals
5 6.2 Properties of Groups of Elements
Physical properties of Alkali Metals
shiny solid at room temperature, malleable, ductile, high melting points, good conductors of heat
and electricity. lower densities than other metals,
largest atomic radius
6 6.2 Properties of Groups of Elements
Alkali metals
Electron configuration
Alkali metals have a single electron in the highest unfilled energy level.
7 6.2 Properties of Groups of Elements
Alkali metals
Li+
Na+
K+
Rb+
Cs+
Fr+
Chemical
Property – they
all form +1 ions.
They react
explosively with
water.
8 6.2 Properties of Groups of Elements
Alkali metals
2:1 ratio with oxygen 1:1 ratio with chlorine
We will see why this happens after we discuss oxygen and chlorine.
9 6.2 Properties of Groups of Elements
Alkaline earth metals
10 6.2 Properties of Groups of Elements
Physical properties of Alkaline Earth Metalsshiny solid at room temperature, malleable, ductile, high melting points, good conductors of heat
and electricity. Slightly smaller atomic radius than
group 1 elements
11 6.2 Properties of Groups of Elements
Electron configuration
Alkaline earth metals have two electrons in the highest unfilled energy level.
Alkaline earth metals
12 6.2 Properties of Groups of Elements
Alkaline earth metals
Be2+
Mg2+
Ca2+
Sr2+
Ba2+
Ra2+
Chemical
property: forms
+2 ions
13 6.2 Properties of Groups of Elements
1:1 ratio with oxygen 1:2 ratio with chlorine
We will see why this happens after we discuss oxygen and chlorine.
Alkaline earth metals
14 6.2 Properties of Groups of Elements
Transition metals
15 6.2 Properties of Groups of Elements
Physical properties of Transition metals
shiny solid or liquid at room temperature, malleable, ductile,
high melting points, good conductors of heat and electricity.
16 6.2 Properties of Groups of Elements
Transition metals
17 6.2 Properties of Groups of Elements
Transition metals
Electron configuration
Transition metals all have electrons in partly filled d orbitals.
18 6.2 Properties of Groups of Elements
Transition metals
Bonding properties are complicated. For bonding with oxygen:
2:1 ratio for silver1:1, 2:3, 3:4 ratios for iron
19 6.2 Properties of Groups of Elements
Carbon, nitrogen, and oxygen
20 6.2 Properties of Groups of Elements
Carbon, nitrogen, oxygen
Extremely important elements
to be discussed separately
21 6.2 Properties of Groups of Elements
Carbon, nitrogen, oxygen
The electron structures makes these elements very flexible in their chemistry.
Nitrogen and oxygen tend to accept electrons
Carbon can accept or donate electrons
22 6.2 Properties of Groups of Elements
Example compounds
Carbon can
bind many
elements,
including itself.
Nitrogen compounds
Carbon compounds
23 6.2 Properties of Groups of Elements
Halogens
24 6.2 Properties of Groups of Elements
Physical properties of Halogens
exhibit highly variable physical properties. Halogens range from solid (I2) to liquid (Br2)
to gaseous (F2 and Cl2) at room temperature.
Highest electronegativities,
smaller atomic radii
25 6.2 Properties of Groups of Elements
Halogens
Halogens have a single open quantum state in the highest energy p orbital.
26 6.2 Properties of Groups of Elements
Halogens
F–
Cl–
Br–
I–
At–
Chemical
property:
form –1 ions.
27 6.2 Properties of Groups of Elements
In their pure forms:Halogens form diatomic molecules (Cl2, F2)They are highly reactive, and toxic to many organisms.
Halogens
When combined with a metal:The resulting compound is generally an ionic salt.
28 6.2 Properties of Groups of Elements
Noble gases
29 6.2 Properties of Groups of Elements
Physical Properties of Noble Gases
The noble gases have low boiling points and are all gases at room temperature. These inert gases
have high ionization energies and almost no value for electronegativity.
30 6.2 Properties of Groups of Elements
The highest energy levels are completely filled.
Electrons in completely filled energy levels do not make bonds.
Noble gases
31 6.2 Properties of Groups of Elements
Noble gases
Elements in group 18 are
called “noble gases”
because they mostly do not
chemically bond with any of
the other elements.
32 6.2 Properties of Groups of Elements
Remember: Electrons are responsible for bonding properties.
Bond formation
1 empty quantum state left in the highest unfilled energy level
1 single electron in the highest unfilled
energy level
33 6.2 Properties of Groups of Elements
18 electrons like argon 10 electrons like neon
By forming the ionic compound sodium chloride, both chloride and sodium ions achieve a noble gas electron structure!
Bond formation
34 6.2 Properties of Groups of Elements
Bond formation
2 empty quantum states left in the highest unfilled energy level
1 single electron in the highest unfilled energy level
Can you form a molecule with hydrogen and oxygen atoms?
35 6.2 Properties of Groups of Elements
Bond formation
Each hydrogen atom donates one electron to the oxygen atom
Oxygen now has 10 electrons, like neon (a noble gas)
36 6.2 Properties of Groups of Elements
Elements that belong to the same period in the periodic table have similar
chemical properties.
This is because they have similar electron configurations, and
electrons are responsible for bonding properties.
A noble gas electron structure is obtained through bond formation.
