3 Bonding

Question 1

What three different kinds of bonds do you know?

Answer 1

1) ionic bonding
2) covalent bonding
3) metallic bonding

Question 2

What are the key words for the formation of an ionic bond?

Answer 2

• outer shell electrons are transferred from metal to non-metal
• after transferring of electron positive (cations) and negative (anions) ions are formed
• outer shells of these ions reach the electronic configuration if the nearest noble gas
• this ions are held together by electrostatic attractions

Question 3

Describe what is an alloy?

Answer 3

An alloy is made by metallic bonding. An alloy is a mixture of two or more metals (sometimes carbon can be mixed to an alloy too).

Question 4

What are the key words for a formation of a metallic bond?

Answer 4

• outer shell electrons become free to move
• outer shell electrons are delocalised and form a sea of electrons
• metal atoms form an array of positive ions
• this array of positive ions is held together by the sea of electrons

Question 5

Answer what kind of bonds do you have in this examples:

a) water
b) brass
c) cooking salt
d) hydrogen
e) chalk

Answer 5

a) covalent
b) metallic
c) ionic
d) covalent
e) ionic

Question 6

What are intermolecular forces? Do you know an example?

Answer 6

Forces of attraction between separate molecules for example water molecules.

Question 7

What kind of bonds can you find in a water molecule?

Answer 7

2 x covalent bond between oxygen and hydrogen atoms.

Question 8

What are the key words for the formation of a covalent bond?

Answer 8

• exists between two non-metals
• outer shell electrons are shared
• outer shells “overlap” to form a covalent bond
• electrostatic attractions between the negative pair of shared electrons and the two positive nuclei

Question 9

Explain why ionic compounds have high melting and boiling points.

Answer 9

• electrostatic attraction between the opposite charged ions

- high amount of energy is needed to overcome this forces of attraction

Question 10

Name the properties of ionic compounds.

Answer 10

• high melting and boiling points
• all solids
• can be soluble or insoluble in water
• non conductor in solid state
• brittle
• often hard

Question 11

Electronic configurations of calcium and oxygen are:
Ca 2,8,2
O 2,6
What ions are formed and what are the electronic configuration of the ions after the formation of calcium oxide?

Answer 11

Ca 2+ [2,8] 2+ (calcium ion)

O 2- [2,8] 2- (oxide ion)

Question 12

What kind of covalent bonds do you find in the oxygen molecule O2? How many electrons are shared between these oxygen ions?

a) single
b) double
c) triple

Answer 12

b) double bond, 4 electrons are shared.

Question 13

What properties do metals have?

Answer 13

• good conductors of electricity and heat
• ductile
• malleable
• shiny
• solids

Question 14

Why are metals good conductors of electricity?

Answer 14

Because the electrons are delocalised and free to move.

Question 15

Explain why the melting and boiling points of covalent compounds show high differences.

Answer 15

Because covalent structures can be molecular (water) or giant covalent (diamond).
In the case of molecules, intermolecular forces are weak and so responsible for low melting and boiling points.
In the case of giant covalent substances, all atoms are bonded together by strong covalent bonds.

Question 16

What metal is a liquid at room temperature?

Answer 16

Mercury Hg

Question 17

What two structures of carbon do you know? Describe these structures briefly.

Answer 17

1) Diamond - each carbon bonds strongly to four other carbon atoms in a tetrahedral arrangement. 3D- structure, therefore diamonds are extremly hard.
2) Graphite - each carbon is bonds to three other carbon atoms. 2D-structure, hexagons, bild layers, therefore not hard.