Simple molecular substances

Question 1

;p;ol;pWhat are simple molecular substances ?

Answer 1

made up of molecules containing a few atoms joined together by covalent bonds

Question 2

examples of simple molecular substances

Answer 2

H2 - only needs one electron to complete the first shell so often forms 1 covalent bonds either with other hydrogen atoms or with other elements.

Cl2 - only needs one electron to complete the shell so 2 chlorines share 1 pair of electrons and form 1 covalent bond

O2 = forms two covalent bonds

N2 = needs three more electrons to makes triple bonds

H20 = oxygen has 6 electrons, hydrogen has one
so hydrogen needed. Oxygen shares pair of electrons with two H atoms

CH4

Question 3

Properties of simple molecular substances

Answer 3

1) Substances containing covalent bonds usually have simple molecular structures
2) The atoms within the molecules are held together by very strong covalent bonds, but the forces of attraction between molecules are very weak

Question 4

What do you need to do to melt or boil a simple molecular compound ( CH4, NH3, CO2, H20 )

Answer 4

Break these feeble intermolecular forces and not the covalent bonds so mp, bp is very low because molecules easily parted from each other

Question 5

Most molecular substances are ..

Answer 5

liquid or gas at room temperature

Question 6

What occurs as molecules get bigger ?

Answer 6

The strength of the intermolecular forces increases so more energy needed to break them so mp, bp increases

Question 7

Do molecular compounds such as H20 or CH4 conduct electricity ?

Answer 7

no because they aren’t charged so there are no free electrons or ions