CHEMICAL FAMILIES Alkali metals Position in the periodic

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CHEMICAL FAMILIES Alkali metals Position in the periodic table Physical properties • OER SOURCES

CHEMICAL FAMILIES Alkali metals Position in the periodic table Physical properties • OER SOURCES • • • . https: //www. khanacademy. org/science/chemistry/periodic-table/copy-of-periodic-table-ofelements/v/periodic-table-introduction https: //www. youtube. com/watch? v=QJe. Tia. Nu. V 78 https: //www. youtube. com/watch? v=ANH-v-jd 9 PQ

Names of elements in group (I) of the periodic table and their electronic arrangement

Names of elements in group (I) of the periodic table and their electronic arrangement ELEMENT Li Na K ATOMIC NO. ELECTRONIC ARRANGEMENT GROUP PERIOD

GROUP TASK putting Li , Na , K metals in their respective position in

GROUP TASK putting Li , Na , K metals in their respective position in the periodic table

Groups report on their group tasks using a skeck of periodic table projected on

Groups report on their group tasks using a skeck of periodic table projected on the • To groups to report on their work ; • Teacher and students can ask questions

correct answers H Li Na K

correct answers H Li Na K

Video clip

Video clip

GRADATION IN SIZE AS WE MOVE DOWN THE GROUP EFFECT OF SIZE OF ATOM

GRADATION IN SIZE AS WE MOVE DOWN THE GROUP EFFECT OF SIZE OF ATOM ON ITS PHYSICAL PROPERTIES i) melting point i)boiling point element Atomic numbe r NO. OF ENERGY LEVELS Li Na K 3 11 19 2 3 4 ATOMIC MELTING RADIUS (nm) POINT(0 C) BOILING POINT ( 0 C)

discussion • Melting point and boiling point decrease down the group due to -Increase

discussion • Melting point and boiling point decrease down the group due to -Increase in the size of atom as we move down the group • This results in decrease in forces holding the atoms together • These forces are known as METALLIC BONDS

conclusion • Alkali metals are placed in group I of the periodic table because

conclusion • Alkali metals are placed in group I of the periodic table because they have 1 electron in the outermost energy level • Atomic radius of the elements increase down the group due to increase in no. of energy levels and electron repulsion • M. p and B. p decrease down the group due to decrease in the strength of metallic bonds

Extended learning assignment What makes alkali metals conductors of electricity? What is ionisation energy

Extended learning assignment What makes alkali metals conductors of electricity? What is ionisation energy • Assignment. ; • Observe the surface of freshly cut sodium and potassium metal and write the observation. • https: //www. youtube. com/watch? v=QJe. Tia. Nu. V 78 • https: //www. youtube. com/watch? v=ANH-v-jd 9 PQ • To be submitted through the class prefect before the next lesson