s block elements

s block elements

LO

• Analyse the properties of  hydroxides and halides  of alkali metals

HYDROXIDES

• All the alkali metals, their oxides, peroxides and superoxides readily dissolve in water to produce corresponding hydroxides which are strong alkalies

Multiple Select

Which of the following is a peroxide

• Na2O2

• Na2O

Multiple Select

Which of the following is a superoxide

• Na2O

• Na2O2

• K2O

• KO2

Basic strength of the hydroxides

• The basic strength of these hydroxides increases as we move  down the group Li to Cs.

• Alkali metals hydroxides being strongly basic react with all acids forming salts.

Thermal stability of group 1 hydroxides

• All these hydroxides are highly soluble in water and thermally    stable except lithium hydroxide

Multiple Select

Reason for the anomalous behaviour of lithium hydroxide

• large radii of lithium ion

• high polarising power of lithium ion

• low ionisation enthalpy

Multiple Choice

A

• A

• B

• C

• D

Multiple Choice

• A

• B

• C

• D

LO

ANALYSE THE PROPERTIES OF HALIDES OF ALKALI METALS

FORMATION OF HALIDES

• ALKALI METALS REACT WITH HALOGENS TO FORM HALIDES

Multiple Choice

LITHIUM HALIDE IS MORE

• COVALENT IN NATURE

• IONIC IN NATURE

Multiple Choice

COVALENT NATURE OF LITHIUM ION IS DUE TO ITS

• LARGE RADIUS

• HIGH POLARISING POWER

REASON FOR THE COVALENT CHARACTER OF LITHIUM

• The lithium ion is small in size and has the tendancy todistort the electron cloud of the negative halide ion

Multiple Select

Which of the lithium halides is more covalent more covalent

• LiF

• LiCl

• LiBr

• LiI

Open Ended

Reason for the high covalent character of lithium iodide

Multiple Select

Alkali metals are good

• oxidising agents

• reducing agents

The alkali metals dissolve in liquid ammonia giving deep blue solutions which are conducting in nature.