Unit 2- Shapes

Question 1

What is the electron pair repulsion theory?

Answer 1

• Electron pairs in the outer shell of atoms and ions repel each other to get as far as possible
• Shape is held due to bonds electrostatic forces

Question 2

What are the shapes and angles for the electron pairs between 2-6?

Answer 2

• 2 e.p = linear= 180
• 3 e.p = trigonal planar - 120
• 4 e.p = tetrahedral - 109.5
• 5 e.p = trigonal bypyramidal- 109.5 and 120
• 6 e.p = octahedral - 90

Question 3

What is the difference between lone pairs and bonded pairs of electrons in shapes of molecules?

Answer 3

• Lone pair held closer than bonded pair
• Lone pair decreases the angle by 2 degrees roughly

Question 4

What are three allotropes of carbon?

Answer 4

• Diamond
• Graphite
• Fullerenes

Question 5

Give an example of a fullerene and explain it

Answer 5

• Buckministerfullerene - bucky balls
• Black solid
• Simple molecular structure
• Soluble in various solvents
• Electrical insulators rather than conductors
• Tubes and spheres can be produced