What do these three substances have in common? Properties of small molecules Quick Starter What do these three substances have in common? show hint show answer

What do these three substances have in common? Properties of small molecules Quick Starter What do these three substances have in common? They are all gases under normal conditions Hint X show hint show answer

What do these three substances have in common? Properties of small molecules Quick Starter What do these three substances have in common? show hint show answer

They are harmful to human health or the climate Properties of small molecules Quick Starter They are harmful to human health or the climate (CO and SO2 are toxic; CO2 can cause suffocation) They all consist of small molecules, with covalent bonds within the molecules and much weaker intermolecular forces between molecules Weak intermolecular forces explains why they are gases even at low temperatures back to question

Learning questions What are simple covalent structures? What do they have in common? Why do they show these properties? Keywords: Simple covalent, melting point, boiling point, properties, attraction, intermolecular forces, weak, conductivity, energy.

What are simple covalent structures? NK What are simple covalent structures? What type of elements are found in covalent compounds? Non-metals only. Why are some structures called simple covalent structures? Just a few atoms joined together by sharing electrons. Not joined to other molecules. Keywords: Simple covalent, melting point, boiling point, properties, attraction, intermolecular forces, weak, conductivity, energy.

What properties do simple covalent molecules have? Lets see if they can conduct electricity. Write down your observations. Explain what you noticed and why you think it happened. Try comparing the simple covalent molecules to the ionic compounds, what is the difference? Try heating a small amount in a boiling tube. What do you notice? What does this tell you about their melting/boiling points? Keywords: Simple covalent, melting point, boiling point, properties, attraction, intermolecular forces, weak, conductivity, energy.

How are the particles arranged in a solid, liquid and a gas? Do a quick diagram to show them. What happens to particles as they get heated? Why do you think this happens?

Main properties of simple covalent molecules Don’t conduct electricity. Low melting and boiling points. Try and explain why this is. Keywords Intermolecular forces, charge, weak, attraction, covalent molecules, electrons, Extension: Why is it dangerous to take electrical appliances near a bath as water doesn’t conduct electricity?

Explaining properties of simple molecules Not conducting electricity Do they have a charge that can move? If not they can’t conduct electricty. Low melting point Whilst they have strong bonds between atoms but weak attractions between molecules which means they can be separated easily. If the molecules are further aoart how does this relate to its state? (solid, liquid, gas)

Compare the properties of sodium chloride and water. Include: Melting point, conductivity, type of bonding, type of structure Keywords: Simple covalent, melting point, boiling point, properties, attraction, intermolecular forces, weak, conductivity, energy.

Key points Sodium chloride Giant ionic structure. Conducts electricity as liquid not as solid. High melting point Water Simple covalent structure. Doesn’t conduct electricity. Low melting point