G10 Pre-IB: Tsang wan hoChristopher makFung keiAlkali Metals1

Alkali metals?Alkali metal Group 1Reactive metals that do not occur freely in nature, often occur in compound formsOnly one electron in their outer shell -> lose one electron in ionic bonding (except hydrogen) to form ions of duplet or octet structuresSame properties as most metals but softerReact vigorously if exposed to water3

Rationale behindFirst Ionization energyEnergy required to remove the most loosely held electron from one mole of gaseous atoms to produce 1 mole of gaseous ions each with a charge of 1+.

First ionization energy of the alkali metals decreases down the group, it is easier for the outermost electron to be removed from the atom and participate inchemical reactions, thus increasing reactivity down the group.Outermost electron: 1)Distance between nucleus & the valence electron2)The shielding effect of inner shell electrons

-1st alkali metal- Least reactive in family- Electronic configuration 1s2,2s1- Density lower than water- Reacts with water, produces hydrogen gas and turns water alkaline- Solid, melting point : 180.5C, boiling point : 1330CUses include:Disposable Lithium and rechargeable Lithium ion batteries.Lithium (3)

Sodium(11)- 2nd alkali metalMore reactive then LithiumElectronic configuration 1s2, 2s2, 2p6, 3s1 Density lower than waterReacts with water, Sodiummeltsfizzes and gives offhydrogen gas and forms sodium hydroxide. Orange flame if lit.Solid , melting point : 97.794C, boiling point : 882.94C

Uses include:- Forming table salt, with chlorine into sodium chloride,- Reacting with water to form sodium hydroxide, hydrogen by product

Strong Alkali

- 3rd alkali metal- More reactive than sodium- Electronic configuration 1s2, 2s2, 2p6, 3s2, 3p6, 4s1 - Density lower than water. Reacts with water vigorously, emitting purple flame. Gives off hydrogen gas and turns water alkaline. Solid, melting point : 63.5C, boiling point : 759C Found abundantly (not overdose)in bananas. ~350mg

Uses include:Fertilizer from Potassium Nitrate compoundPotassium (19)

- 4th alkali metal- More reactive than Potassium- Electronic configuration 1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s2, 4p6, 5s1 Reacts very vigorously with water, explosive, emits purple flame and gives off hydrogen gas and turns water alkaline. Solid, melting point : 39.3C, boiling point : 688C

Uses include:Rubidium atomic clock, uses electrons from Rb to control oscillating electric signal

Rubidium (37)

Robert BunsenandGustav Kirchhoff(1861)- 5th alkali metal- More reactive than rubidium- Least electronegative element (tendency to attract electron to itself)- Electronic configuration 1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s2, 4p6, 4d10, 5s2, 5p6, 6s1 Reacts extremely vigorously with water, explosive, emits violet flame and gives off hydrogen gas and turns water alkaline. Solid, melting point : 83.3C, boiling point : 671C

Uses include:Used as material that combines with and removes trace gases from vacuum tubes due to its oxygen affinityCaesium(55)

Carl Setterberg(1882)- 6th alkali metal- Most reactive in the group- 2nd least electronegative element- Most unstable naturally occurring element- Radioactive, half-life of 22 mins- Electronic configuration 1s2,2s2, 2p6, 3s2, 3p6, 3d10, 4s2, 4p6, 4d10, 5s2, 5p6, 4f14, 5d10, 6s2, 6p6, 7s1 It is supposedly the most vigorous of all alkali metals, but not tested due to its high heat of decay and short half-life.- Solid, melting point : 27C, boiling point : 677C ( uncertain )No known usageFrancium(87)

Marguerite Perey(1939)We hope you have learnt more about alkali metals through this project.

Thank youThis is the end of our presentationhttps://en.wikipedia.org/wiki/Alkali_metal

www.chemicalelements.com/groups/alkali.html

www.rsc.org/.../2015/01/alkali-metal-explosion-explained

https://www.youtube.com/playlist?list=PL8dPuuaLjXtPHzzYuWy6fYEaX9mQQ8oGr

https://www.google.com.hk/search?q=alkali+metals&oq=alkali+metals&aqs=chrome..69i57j69i61l3.44573j0j4&sourceid=chrome&es_sm=119&ie=UTF-8

References

The term "shielding effect" refers to a decrease in attraction between electrons and the nucleusin an atom. Electrons are highly attracted to the nucleus, because they have a negative chargeand the nucleus contains protons, which have apositive charge. When additional electrons are present in different orbits, the electrons repel each other slightly. This repulsion force works against the nucleus attraction force, decreasing the attraction between the electrons and the nucleus.Shielding effect