1.31​ ​Explain​ ​the​ ​formation​ ​of​ ​simple​ ​molecular,​ ​covalent​ ​substances,​ ​using dot​ ​and​ ​cross​ ​diagrams

Question 1

Top Left – Hydrogen (H₂)
Two hydrogen atoms share one pair of electrons.
Each hydrogen ends up with 2 electrons in its outer shell (stable).

Answer 1

Question 2

Top Right – Hydrogen Chloride (HCl)
Hydrogen shares one electron with chlorine.
Chlorine ends up with a full outer shell (8 electrons).
Hydrogen has 2 electrons in its shell (also stable).

Answer 2

Question 3

Middle Left – Water (H₂O)
One oxygen atom shares electrons with two hydrogen atoms.
Oxygen also has lone pairs (non-bonded electrons).
Bent molecule shape due to electron repulsion.

Answer 3

Question 4

Middle Right – Methane (CH₄)
Carbon shares one electron with each of four hydrogen atoms.
Carbon has a full outer shell (8 electrons).
Tetrahedral shape (not shown in 3D here).

Answer 4

Question 5

Bottom Left – Oxygen (O₂)
Two oxygen atoms share two pairs of electrons (a double bond).
Each oxygen has 4 non-bonded electrons (2 lone pairs).

Answer 5

Question 6

Bottom Right – Carbon Dioxide (CO₂)
Carbon forms double bonds with each oxygen atom.
Linear shape molecule.
Oxygen atoms have 4 non-bonded electrons each.

Answer 6