Elliot has some stearic acid. It is in the solid state. a Describe how Elliot could use the apparatus below to measure the melting point of his stearic acid. (2 marks) End-of-chapter test Chapter 2 Foundation © Oxford University Press 2015 www. oxfordsecondary. co. uk/acknowledgements This resource sheet may have been changed from the original. b Elliot writes a results table for his experiment. Complete the table by writing in the missing column heading. Include units. Time (min) () (1 mark) c Elliot does his experiment and writes his results in the table. He uses his results to draw a graph. i Write down the melting point of stearic acid. oC (1 mark) ii Draw a line on the graph to show how its shape would be different if the stearic acid was not pure.

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.