Molecular Geometry and Bonding in HCN

The video tutorial explains how to determine the molecular geometry of hydrogen cyanide (HCN). It begins with constructing a valid Lewis structure, highlighting the central carbon atom bonded to hydrogen and nitrogen. The steric number is determined, and the absence of lone pairs is noted, leading to a linear molecular geometry. The tutorial visualizes this geometry in three dimensions, showing the bond angles of 180 degrees. The AXE notation is introduced to further confirm the linear geometry, with 'A' as the central atom, 'X' as the bonded atoms, and 'E' as the lone pairs. The video concludes by summarizing the linear geometry of HCN.

What is the first step in determining the molecular geometry of HCN?

• Calculate the molecular weight.

• Identify the bond angles.

• Draw a valid Lewis Structure.

• Measure the bond lengths.

What is the steric number of the central carbon atom in HCN?

• Three

• Two

• One

• Four

How many lone pairs are present on the central carbon atom in HCN?

• Two

• Zero

• Three

• One

What is the molecular geometry of HCN?

• Bent

• Tetrahedral

• Trigonal planar

• Linear

What is the bond angle in the linear geometry of HCN?

• 90 degrees

• 120 degrees

• 109.5 degrees

• 180 degrees

In AXE notation, what does 'X' represent for HCN?

• The central atom

• The type of bonds

• The number of lone pairs

• The number of atoms bonded to the central atom

What is the AXE notation for HCN?

• AXE2

• AX2

• AX2E

• AX3