Presentation on theme: "1 Choose An Element…. 2 Smoke Particles If a cell containing smoke is observed through a microscope; the smoke particles are seen to move around erratically."— Presentation transcript:
2 Smoke Particles If a cell containing smoke is observed through a microscope; the smoke particles are seen to move around erratically. The effect is caused by larger, visible smoke particles undergoing collisions with smaller, invisible air particles. The effect is known as Brownian Motion.
9 Fluorine Fluorine exists as a yellow diatomic gas at room temperature. Fluorine is the most reactive of the halogens as it is at the top of group seven and reactivity decreases as you descend the group. Fluorine has many uses which include fluorine compounds being added to toothpaste to help protect our teeth. Fluorine compounds are often added to drinking water to also help protect our teeth. Fluorine is a diatomic gas Fluorine is also used to make TEFLON TM, a low friction plastic.
13 Exercise: Antoine Lavoisier 1.What nationality was Antoine Lavoisier? 2.Which book did Lavoisier write that is considered the first modern textbook? 3.How many elements were described in Lavoisier’s book? 4.Into which four groups were these elements placed? 5. Give two mistakes with Lavoisier’s list. French ‘Elements of Chemistry’ (1789) There were 33 elements in his list Metals, non-metals, gases and earths Light and caloric were described as elements, some elements that were listed were later found to be compounds