BTEC Applied Science: Unit 9 Learning aim C
How many electrons can an s subshell hold? - ANSWER 2
How many electrons can a p subshell hold? - ANSWER 6
How many electrons can a d subshell hold? - ANSWER 10
What is Hund's rule? - ANSWER Orbitals must all be singly filled before they can be
doubly occupied
Define the term ionic bond - ANSWER The electrostatic attraction between
oppositely charged ions
What is the charge of an ion from group 1? - ANSWER +1
What is the charge of an ion from group 2? - ANSWER +2
What is the charge of an ion from group 6? - ANSWER -2
What is the charge of an ion from group 7? - ANSWER -1
Explain how atoms of sodium react with atoms of chlorine - ANSWER Na loses its
2s1 electron gaining a +ve charge.
Cl gains an electron in the 3p subshell gaining a -ve charge.
The opposite charges attract to form NaCl
Why do ionic bonds have such high melting points? - ANSWER Each +ve ion is
surrounded by 6 -ve ions and vice versa.
Strong electrostatic attraction in every direction.
Requires a large amount of energy to break
State two factors that affect the strength of an ionic bond - ANSWER Size of ion and
charge on ion
When can ionic substances conduct electricity? - ANSWER When molten or in
aqueous solution
Describe the properties of ionic compounds - ANSWER Conduct electricity when
molten or aqueous solution
High melting/boiling points
Usually soluble in water
Define the term covalent bond - ANSWER A shared pair of electrons
Which metals lose electrons from the 4s subshell before the 3d subshell? -
ANSWER Transition metals
, Why do metals have such high melting points? - ANSWER Strong force of attraction
between positive ions and delocalised electrons. This requires a large amount of
energy to overcome.
State the two factors that affect the strength of metallic bonding - ANSWER Size of
ion
Charge on ion
Explain how the charge on metal ions affects the strength of the metallic bond -
ANSWER The larger the +ve charge the greater the attraction between the nucleus
and the delocalised electrons
Explain how the size of the metal ions affects the strength of the metallic bond -
ANSWER The smaller the +ve ion the closer the nucleus is to the delocalised
electrons creating a greater attraction
Explain why metals conduct electricity - ANSWER The delocalised electrons 'carry'
charge. Current flows because of this.
Explain why metals conduct heat - ANSWER Particles are paced tightly so kinetic
energy is passed from ion to ion. The delocalised electrons also enable heat to be
passed.
Explain why metals are ductile and malleable - ANSWER The lattice structure
allows layers of metal ions to slide over each other without disrupting bonding
Name the 3 forces between molecules - ANSWER Van der Waals
Permanent dipole-dipole
Hydrogen bonds
Order the 3 forces between molecules in order of strongest to weakest - ANSWER
Hydrogen bonds
Permanent dipole-dipole
Van der Waals
How are Van der Waal's forces formed? - ANSWER Electrons move to one side,
caused temporary dipole. This induces a temporary dipole in neighbouring
molecules. Attraction occurs between oppositely charged dipoles
In what molecules do Van der Waal's forces exist? - ANSWER Non-polar molecules
How are permanent dipole-dipole forces formed? - ANSWER Permanent dipole in
one molecule attracts oppositely charged permanent dipole in neighbouring molecule
In which molecules do permanent dipole-dipole forces exist? - ANSWER Polar
molecules
Which elements must be present for hydrogen bonds to exist? - ANSWER
Hydrogen and either nitrogen, oxygen or fluorine
How many electrons can an s subshell hold? - ANSWER 2
How many electrons can a p subshell hold? - ANSWER 6
How many electrons can a d subshell hold? - ANSWER 10
What is Hund's rule? - ANSWER Orbitals must all be singly filled before they can be
doubly occupied
Define the term ionic bond - ANSWER The electrostatic attraction between
oppositely charged ions
What is the charge of an ion from group 1? - ANSWER +1
What is the charge of an ion from group 2? - ANSWER +2
What is the charge of an ion from group 6? - ANSWER -2
What is the charge of an ion from group 7? - ANSWER -1
Explain how atoms of sodium react with atoms of chlorine - ANSWER Na loses its
2s1 electron gaining a +ve charge.
Cl gains an electron in the 3p subshell gaining a -ve charge.
The opposite charges attract to form NaCl
Why do ionic bonds have such high melting points? - ANSWER Each +ve ion is
surrounded by 6 -ve ions and vice versa.
Strong electrostatic attraction in every direction.
Requires a large amount of energy to break
State two factors that affect the strength of an ionic bond - ANSWER Size of ion and
charge on ion
When can ionic substances conduct electricity? - ANSWER When molten or in
aqueous solution
Describe the properties of ionic compounds - ANSWER Conduct electricity when
molten or aqueous solution
High melting/boiling points
Usually soluble in water
Define the term covalent bond - ANSWER A shared pair of electrons
Which metals lose electrons from the 4s subshell before the 3d subshell? -
ANSWER Transition metals
, Why do metals have such high melting points? - ANSWER Strong force of attraction
between positive ions and delocalised electrons. This requires a large amount of
energy to overcome.
State the two factors that affect the strength of metallic bonding - ANSWER Size of
ion
Charge on ion
Explain how the charge on metal ions affects the strength of the metallic bond -
ANSWER The larger the +ve charge the greater the attraction between the nucleus
and the delocalised electrons
Explain how the size of the metal ions affects the strength of the metallic bond -
ANSWER The smaller the +ve ion the closer the nucleus is to the delocalised
electrons creating a greater attraction
Explain why metals conduct electricity - ANSWER The delocalised electrons 'carry'
charge. Current flows because of this.
Explain why metals conduct heat - ANSWER Particles are paced tightly so kinetic
energy is passed from ion to ion. The delocalised electrons also enable heat to be
passed.
Explain why metals are ductile and malleable - ANSWER The lattice structure
allows layers of metal ions to slide over each other without disrupting bonding
Name the 3 forces between molecules - ANSWER Van der Waals
Permanent dipole-dipole
Hydrogen bonds
Order the 3 forces between molecules in order of strongest to weakest - ANSWER
Hydrogen bonds
Permanent dipole-dipole
Van der Waals
How are Van der Waal's forces formed? - ANSWER Electrons move to one side,
caused temporary dipole. This induces a temporary dipole in neighbouring
molecules. Attraction occurs between oppositely charged dipoles
In what molecules do Van der Waal's forces exist? - ANSWER Non-polar molecules
How are permanent dipole-dipole forces formed? - ANSWER Permanent dipole in
one molecule attracts oppositely charged permanent dipole in neighbouring molecule
In which molecules do permanent dipole-dipole forces exist? - ANSWER Polar
molecules
Which elements must be present for hydrogen bonds to exist? - ANSWER
Hydrogen and either nitrogen, oxygen or fluorine
