1. Extended Only

The electron distribution of a selenium atom is 2 + 8 + 18 + 6.

i) Selenium forms an ionic compound with potassium. Draw a diagram which shows the formula of this ionic compound,  the charges on the ions and the arrangement of the outer electrons around the negative ion. Use o to represent an electron from an atom of potassium. Use x to represent an electron from an atom of selenium.

[3]

ii) Draw a diagram showing the arrangement of the outer electrons in one molecule of the covalent compound selenium chloride. Use x to represent an electron from an atom of selenium. Use o to represent an electron from an atom of chlorine.

[3]

iii) Predict two differences in the physical properties of these two compounds.

[2]