Hi everyone I am…… from Group 13 Today's topic is calcium My presentation is in parts In the first part history, then in the second part introduction, next Chemical properties, finally uses of calcium I will start with History 1) History ( Lịch sử) Lime (calcium oxide, CaO) was the useful material obtained by heating limestone and used for centuries to make plaster and mortar Calcium compounds were known for millennia, although their chemical makeup was not understood until the 17th century Lime as a building material and as plaster for statues was used as far back as around 7000 BC The first dated lime kiln dates back to 2500 BC and was found in Khafajah, Mesopotamia In 1808, pure calcium was isolated by electrolysis of lime and mercury oxide by Humphry Davy …… will be the presenter of the next part I am Trinh from Group 13 So now I come to the next part, which is introduction 2) INTRODUCTION (Giới thiệu) Calcium (Ca), chemical element, one of the alkaline-earth metals of Group (IIa) of the periodic table It is the most abundant metallic element in the human body and the fifth most abundant element in Earth’s crust It crystallises in the face-centered cubic arrangement like strontium Calcium is a very ductile silvery metal Calcium metal melts at 842 °C and boils at 1494 °C Its density of 1.55 g/cm3 is the lowest in its group 3) Chemical properties ( tính chất hóa học) Please watch the video of the reaction of calcium with acid and water 4) Uses of calcium ( công dụng) Calcium is important for our body to run It helps build strong bones and teeth, and it allows our muscles and brain cells work Calcium is an important substance in the building industry, because calcium hydroxide (Ca(OH)2 is used in cement and mortar Calcium carbonate is also used in plastics and adhesives as a filler Because calcium oxide (CaO) neutralizes acid it can be used to decrease the effects of acid rain in rivers and lakes Calcium is also commonly used in heartburn and antacid tablets Thank you for listening