7. COVALENT BONDING

Question 1

1. Do all atoms like to gain or lose electrons?

Answer 1

• no
• they do still need to achieve an octet configuration for maximum stability

Question 2

2. How can atoms that do not partake in ionic bonding complete their outer shell configurations?

Answer 2

• they can fill their outer shells by sharing electrons with other atoms
• these atoms can overlap

Question 3

3. How does the covalent bonding of the diatomic hydrogen molecule occur?

Answer 3

• each H atom has a 1s electronic configuration
• each H atom needs one electron to form a stable (H) noble gas configuration
• the negative electrons in the outermost shell of the one hydrogen atom are attracted to the positive protons in the nucleus of the other hydrogen atom
• the electron clouds are pulled towards one another’s positive nucleus’s
• the electron clouds start to form a tear drop shape
• they are distorted
• this process is known as polarisation
• their Coulombic attraction to the negative electrons keeps the nuclei bound to each other
• there is a transfer of electrons between the two H atoms
• this bring about an equilibrium state
• once the electrons are shared
• the repulsive forces stop the two hydrogen atoms from continuing to move closer to one another

Question 4

4. What do two shared electrons form?

Answer 4

• a single covalent bond

Question 5

5. How does the covalent bonding for O2 occur?

Answer 5

• oxygen is in group six
• this means that it needs 2 valence electrons to fill up its outermost shell
• this would allow it to respect the octet rule
• and to gain stability
• two oxygen atoms can combine together
• they overlap their valence shells
• they share a total of four electrons

Question 6

6. What is the sharing of 4 electrons known as?

Answer 6

• a double covalent bond

Question 7

7. How does the covalent bonding of N2 occur?

Answer 7

• Nitrogen is in group 5
• this means that it needs three valence electrons to fill up its outermost shell
• this would allow it to respect the octet rule
• and to gain stability
• two Nitrogen atoms join together by overlapping their valence shells
• they share a total of six electrons

Question 8

8. What is the sharing of 6 electrons known as?

Answer 8

• a triple covalent bond

Question 9

9. Which elements are usually covalently bonded?

Answer 9

• two non-metal atoms

Question 10

10. How does the covalent bonding of the atoms within a water molecule occur?

Answer 10

• a water molecule (H2O) consists of two hydrogen atoms and one oxygen atom
• Oxygen is in group six
• it needs two valence electrons to fill its outermost shell
• this would allow it to respect the Octet rule
• and to gain stability
• hydrogen needs one valence electron to fill its outermost shell
• 1 oxygen atom overlaps with two hydrogen atoms
• this results in 2 single covalent bonds forming
• along with 2 lone pairs

Question 11

11. How does the covalent bonding of methane occur?

Answer 11

• Methane (CH4) consists of one Carbon atom and 4 Hydrogen atoms
• Carbon is in group 4
• it needs 4 valence electrons to fill up its outermost shell
• this would allow it to respect the Octet rule
• and to gain stability
• hydrogen is in group 1
• it needs only one valence electron to complete its outermost shell
• this would allow it to gain stability
• the 4 hydrogen atoms and the 1 carbon atom join together
• this results in 4 single covalent bonds forming

Question 12

12. How does the covalent bonding of Ammonia occur?

Answer 12

• Ammonia (NH3) consists of one nitrogen atom and three hydrogen atoms
• Nitrogen is in group 5
• it requires three valence electrons to fill up its outermost orbital
• this would respect the Octet rule
• and result in stability for the Nitrogen atom
• hydrogen is in group 1
• it only requires one valence electron to complete its outermost shell
• the one Nitrogen atom joins with the 3 hydrogen atoms
• this results in 3 single covalent bonds forming
• and one lone pair forming

Question 13

13. How does the covalent bonding of Carbon Dioxide occur?

Answer 13

• Carbon Dioxide consists of one carbon atom and two oxygen atoms
• Carbon is in group 4
• it requires 4 valence electrons to complete its outermost shell
• this will result in a complete s2p6 electron configuration
• this will provide the carbon atom with stability
• Oxygen is in Group 6
• it requires 2 valence electrons to complete its outermost shell
• this will result in a complete s2p6 electron configuration
• this will provide the carbon atom with stability
• the two oxygen atoms and the carbon atom join together
• this results in 2 double covalent bonds
• and 2 lone pairs

Question 14

14. How does the covalent bonding of Nitrogen Trifluoride occur?

Answer 14

• NF3 consists of one nitrogen atom and three Fluorine atoms
• Nitrogen is in group 5
• it requires 3 valence electrons to complete its outermost shell
• this will result in a complete s2p6 electron configuration
• this will provide the carbon atom with stability
• Fluorine is in group 7
• it requires 1 valence electron to complete its outermost shell
• this will result in a complete s2p6 electron configuration
• this will provide the carbon atom with stability
• the one nitrogen atom and the 3 fluorine atoms join together
• this results in 3 single covalent bonds
• one lone pair on the nitrogen atom
• 3 lone pairs on each fluorine atom (9 lone pairs)

Question 15

15. Read through this summary.
    Does everything make sense?

Answer 15

• yes