Alkali MetalsAlkali Metals

Squeaky pop!!

Or

Group 1 Metals

Mr R. Tucker (PP02_2005)

Li

NaK

RbCsFr

Which Group?Which Group?Q ….Q ….Where are they in the Periodic Where are they in the Periodic

Table??Table?? A… Group 1

Mr R. Tucker (PP02_2005)

Are Alkali Metals Are Alkali Metals Hard ?Hard ?

LithiuLithiumm

SodiuSodiumm

PottasiumPottasium

•Alkali Metals are SOFT when cut, producing a shinny surface, which QUICKLY tarnishes in air.

Properties of Alkali Properties of Alkali MetalsMetalsAll alkali (group 1) metals react violently with water, forming

Hydrogen gas and Hydroxides (pH above 7):

ie., Lithium + Water Hydrogen + Lithium Hydroxide

Alkali metals are:

•Metals found in group 1 of the periodic table

•Soft when cut (compared to other metals)

•Metals with low melting points and densities

•Metals which tarnish in air (form white oxides with oxygen)

Question: Why are alkali metals stored under oil? A.. They react with water in

the air

Similar Reactions of Similar Reactions of alkali metals with wateralkali metals with waterMetal Changes ActivityLithium Floats, fizzes, releases

hydrogen, moves about, alkali formed

Third place

3rd

Sodium As before, but metal melts to a bead

Second place

2nd

Potassium As sodium, but hydrogen gas burns with a lilac flame,

can explode on water surface

First place

1stMr R. Tucker (PP02_2005)

Alkali MetalsAlkali Metals• In order of increasing atomic number the alkali metals are:

• Lithium•Sodium

•Potassium•Rubidium •Caesium•Francium

Increasing atomic number

Mr R. Tucker (PP02_2005)

Alkali Metals - increasing Alkali Metals - increasing reactivity reactivity downdown a metal a metal

groupsgroups• In order of increasing atomic number the alkali metals are:

• Lithium•Sodium

•Potassium•Rubidium •Caesium•Francium

Increasing atomic size

Mr R. Tucker (PP02_2005)

Outermost shell electrons are farther away from nucleus

More easily lost

Flame coloursFlame colours of of alkali metal alkali metal compoundscompoundsCompound Flame colour seen

Lithium compounds Red

Sodium compounds Bright yellow

Potassium compounds

Lilac

Mr R. Tucker (PP02_2005)

ReactivityReactivity • These elements

are highly reactive metals.

• The reactivity increases on descending / going down the Group from lithium to caesium.

Videos on youtubeVideos on youtube

Cutting Alkali metals and their reactions with in waterhttps://www.youtube.com/watch?v=uixxJtJPVXk

Violent Reaction (Explosion) of Alkali Metals with Waterhttps://www.youtube.com/watch?v=HvVUtpdK7xw

What if What if the the Most reactive metal element Most reactive metal element reacts reacts

with with the Most reactive non-metal elementthe Most reactive non-metal element in in the periodic table?the periodic table?

What if What if the the Most reactive metal element Most reactive metal element reacts reacts

with with the Most reactive non-metal elementthe Most reactive non-metal element in in the periodic table?the periodic table?

What is the Most reactive metal in the periodic table?It should be Francium, but Fr is radioactive and is extremely difficult to be used in laboratory experiment (half-life is 22 min). Instead Caesium is used here

What is the Most reactive non-metal in the periodic table?

Fluorine

What if What if the the Most reactive metal element Most reactive metal element reacts reacts

with with the Most reactive non-metal elementthe Most reactive non-metal element in in the periodic table?the periodic table?

Reacting Fluorine with Caesium - First Time on Camerahttps://www.youtube.com/watch?v=TLOFaWdPxB0