CHAPTER 6 Elements and the Periodic Table 6.2 Properties of Groups of Elements.

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.