Hóa 1. BONDING.VB and MO, IMF

Bonding Theories

MO
VB

Molecular Bond Theory - Thuyết orbital phân tử (MO)

Molecular shape and overlapping of orbitals

This interaction of atomic orbitals, which gives rise to the molecular orbitals, may also be represented in the form of an orbital (electron) energy diagram

​Molecular shape: hình dạng phân tử
Overlap: xen phủ
Interaction: tương tác

VB. Sigma Bond - liên kết sigma

The strongest type of covalent chemical bond.
They are formed by head-on overlapping between atomic orbital

Liên kết sigma hình thành khi orbital xen phủ trên trục nối nhân

VB. Pi Bond - liên kết Pi

two lobes of an orbital on one atom overlap two lobes of an orbital on another atom and this overlap occurs laterally

Liên kết pi hình thành bằng cách xen phủ song song

VB. Hybridization - Lai hóa

Atomic orbitals (AO) fuse to form newly hybridized orbitals, which in turn, influences molecular geometry and bonding properties.


Molecular geometry: vị trí/hình dạng/định hướng phân tử

Bond Polarity - Sự phân cực liên kết

non polar molecules share electrons equally

non polar molecules: phân tử không phân cực - liên kết giữa 2 hoặc nhiều nguyên tử cùng loại

Bond Polarity

polar molecules share electrons unequally

polar molecule: phân tử phân cực - liên kết giữa 2 hoặc nhiều nguyên tử khác loại, có sự khác biệt độ âm điện giữa các nguyên tử - cặp electron dùng chung (share electrons) phân bố bị lệch giữa 2 nguyên tử

Polar Bonds

differ in electronegativity












electronegativity (EN): độ âm điện

Dipole Molecules - Phân tử phân cực

 atoms in a molecule have substantially different electronegativity: One atom attracts electrons more than another, becoming more negative, while the other atom becomes more positive


attract: hút

Intramolecular Forces (IMF) - Lực liên phân tử

Can determine state of matter at a given temperature

Viscosity

Surface tension
Boiling point
Melting point

​determine: xác định
state: pha (VD: rắn (solid), lỏng (liquid), hơi (gas)
viscosity: độ nhớt
surface tension: sức căng bề mặt

Van Der Waals dispersion

The motion of the electron creates a temporary polarization (in both polar and nonpolar covalent bonds)

dispersion force: lực phân tán
temporary: tạm thời
lực phân tán: tôn tại trong tất cả phân tử hữu cơ

Dipole-Dipole - lưỡng cực - lưỡng cực

Molecules have permanent dipole moment.


permanent dipole: lưỡng cực vĩnh viễn
Trong phân tử phân cực có sự tồn tại moment lưỡng cực, nên giữa các phân tử này có tương tác lưỡng cực-lưỡng cực.

Hydrogen Bond - liên kết hydro

The strongest of the intermolecular forces.
Hydrogen bond exist between molecules that have F-H, O-H, N-H bonds

​LK hydro là tương tác mạnh nhất trong số các lực liên phân tử Intermolecular force: lực liên phân tử

Multiple Choice

p_x - p_x overlap (perpendicular to internuclear axis) is a _______

• undefined

• $$\pi\ Bond$$  

Multiple Choice

s-s overlap is a _______

• $$\pi\ Bond$$  

• σ bond

Multiple Choice

A pi bond can only result from

• overlap of two s orbitals

• side-by-side overlapped of two p orbitals

• end-to end overlapped of two p orbitals

• overlap of hybrid orbitals

Multiple Choice

Water's boiling point is significantly elevated due to this intermolecular force.

• hydrogen bonding

• ionic bonding

• covalent bonding

Multiple Choice

The correct ranking of intermolecular forces in order of greatest to least

• dipole-dipole, Hydrogen bonding, van der Waal forces

• van der Waal forces, hydrogen bonding, dipole-dipole attraction

• Hydrogen bonding, dipole-dipole attraction, van der Waals forces

• van der waal forces, dipole-dipole attractions, Hydrogen bonding

Multiple Choice

Which of the following compounds consists of dipole molecules?

• H₂S

• CH₄

• CO₂

• N₂

Multiple Choice

What is the basis of hydrogen bond?

• Attraction forces between hydrogen atom bonded with another hydrogen atom

• Attraction forces between hydrogen atom bonded with a high electronegativity atom (F, O, N)

• Attraction forces between hydrogen atom bonded with a high electronegativity atom (F, O, N) with atom (F, O, N) of another molecule

• Attraction forces between hydrogen atom with another hydrogen atom of another molecule

Multiple Choice

Pi bonds are formed by 

• side to side overlap of s orbitals
• end to end overlap of s orbitals
• side to side overlap of p orbitals
• end to end overlap of p orbitals

Multiple Choice

Intermolecular forces for: CO₂

• Dispersion Force

• Dipole dipole

• Hydrogen bonding

Multiple Choice

Intermolecular force present in HCl?

• dipole dipole
• dispersion
• H-bond
• ionic

Multiple Choice

Hydrocarbons will have which type of intermolecular forces?

• Dispersion
• dipole
• hydrogen bonds

Multiple Choice

Type of intermolecular force present in I₂, Br₂, and Cl₂.

• dipole dipole
• H-bond
• dispersion
• metallic

Multiple Choice

H₂S has what kind of intermolecular force?

• dipole dipole
• dispersion
• H-bond
• ionic

Multiple Choice

Which of the following has the lowest boiling point?

• CaCl₂
• PH₃
• Cl₂
• N₂

Multiple Choice

Intermolecular forces for: NH₃

• Dispersion Force

• Dipole dipole

• Hydrogen bonding

• covalent bond

Multiple Choice

What explains the very high melting and boiling point of water

• Strong dipole-dipole bonds between water molecules
• Strong hydrogen bonds between water molecules
• Dispersion forces which are present in all molecules
• Asymmetrical shape of the polar bonds.

Multiple Choice

Does H₂O have hydrogen bonding?

• yes
• no

Multiple Choice

Does HF have hydrogen bonding?

• yes
• no

Multiple Choice

Which substance has the weakest intermolecular forces?

• Substance A, boiling point of 75 °C

• Substance B, boiling point of 105 °C

• Substance C, boiling point of 25 °C

• Substance d, boiling point of 45 °C