The s-Block Elements Flashcards
(15 cards)
S-Block- refer to elements found in which group?
collective name for elements found in Group 1 and Group 2 of the periodic table.
what is the electronic configuration of group 1 and group 2 elelments?
ns1 and ns2
what is the geometry for group 1 elements?
body-centred cubic (bcc)
what is the geometry for group 2 elements
All group 2 elements except barium and radium adopt
a hexagonal-closed packed (hcp) geometry.
why does the atomic radii of group 1 elemnts decrease?
due to the effect of increasing atomic radii rather than
changesin Zeff
list 4 basi properties of group 1 elements
- have weak metallic bonds as each atom only contributes one electron towards bonding.
Reactive metals and typically stored under oil
-Density and melting points decrease down the group. - Lithium, sodium and potassium are less dense than water (floating metals if they weren’t reacting)
- Cesium melts at 29 oC
discuss the standard potential of group 1 elements
-Group 1 metals are readily oxidised
-The standard potentials of the M+/ M couples are large and negative.
-Lithium is the strongest reducing agent in water.
-Reducing ability increases from sodium to caesium.
alkali metals react with water to produce?
yield hydrogen gas and an alkali metal hydroxide, MOH.
-Lithium – gentle
reaction with bubbling
-Sodium- reacts rapidly with
the evolution of heat.
-Potassium reacts so violently
that the hydrogen produced
bursts instantly into flame
-Rubidium – explosively
as Rb sinks in water
-Cesium – explosively.
Metal also sinks
Discuss the reaction of Nitrogen with alkli metals
Lithium reacts with nitrogen gas to form lithium nitride, Li3N
- Other alkali metals DO NOT react with nitrogen.
-Very high lattice energy due to the small size of the lithium cation
reaction of alkali metals with Halogens and Hydrohalic acids
Ø Provides halides that are colourless ionic solids with high melting points.
