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Alkali Metals. Li. Na. Or. K. Rb. Group 1 Metals. Squeaky pop!!. Cs. Fr. Mr R. Tucker (PP02_2005). Alkali 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).
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Alkali Metals Li Na Or K Rb Group 1 Metals Squeaky pop!! Cs Fr Mr R. Tucker (PP02_2005)
Alkali 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)
Which Group?Q ….Where are they in the Periodic Table?? A…Group 1 Mr R. Tucker (PP02_2005)
Properties of Alkali Metals All 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 • Powerful reducing agents and form univalent compounds • Metals which tarnish in air Question:Why are alkali metals stored under oil? A.. They react with water in the air Mr R. Tucker (PP02_2005)
Reactions of alkali metals with water (with phenolphthalein indicator present). Mr R. Tucker (PP02_2005)
Are Alkali Metals Hard ? Sodium Lithium • Alkali Metals are SOFT when cut, producing a shinny surface, which QUICKLY tarnishes in air. Pottasium
Flame colours of alkali metal compounds Mr R. Tucker (PP02_2005)
Reactivity • These elements are highly reactive metals. • The reactivity increases on descending the Group from lithium to caesium. • There is a closer similarity between the elements of this Group than in any other Group of the periodic table. Mr R. Tucker (PP02_2005)
Classwork Copy out the text below and fill in the missing gaps: 1 The elements in Group ………….. of the periodic table are known as the ………….. metals because they form …………………..which dissolve in water to give alkaline solutions.They are metals with ………….. density and the first three in the Group are less dense than water, and so ………….. .They have unusually low ………….. points and the solids are quite ………….. . They react with non-metals such as oxygen and ………….. , forming ………….. compounds in which the metal ion carries a charge of ………….. . These salt-like chloride compounds are ………….. solids which dissolve in water to form neutral solutions of pH ………….. The oxides dissolve in water forming the hydroxide solution of pH ………….. hydroxides Alkali low float melting soft salt chlorine +1 ionic 7 14 Mr R. Tucker (PP02_2005)