Chemical Bond Flashcards
(31 cards)
What e- take part in chemical bonds
Valence e-
What are chemical bonds
Chemical bonds=interactions that account for the association of atoms into molecules, ions and crystals
Why do atoms form chemical bonds
To achive more stable electronic confoguration
What impact do chemical bonds have on the energy of the system
They minimize the total energy of the system
What does miminun of the potential energy curve corresponds to
Bond formation. The deeper the curve is=stronger the bond
What is the bond energy
Measure of bond strength of a chem.bond. it is the amount of energy needed to break the atoms involved in chem.bond into free atoms
What is bond length
It is defined as the mean distance between the centers of 2 atoms in a molecule. The smaller the distance=more stable the bond
What is bond angle
Angle between 2 bonds, usually measured in degrees
What is bond angle related to
Dimension and electronegativity of the atoms forming a bond
How can e- behave in a bond
- It can be shared=>non electrostatic bond; covalent bond
- It can be transfered from one atom to another=>electrostatic bond; ionic bond
Explain polarity of covalent bonds
If the atoms have same electronegaticity is is non polar covalent bond.(H-H)
If they have different electronegativity e- isn’t located exactly on the middle but closer to the nucleus of more electronegatice atom which forms dipoles. That is polar covalent bond
What is Lewis structure
Bidimensional representation of the structiral formula and it doesnt give information abt 3D structure
Explain how is Lewis structure written
Dots are used for valence e-.Lines are drawn for bonds. Lond pairs are drawn as pair of dots
Characteristic of ionic compounds
-solid crystals
-high melting temperature
-the melted compound conducts electrcity
-they can dissolve in water and comduct electricity
Explain formation of crystalline solid
There is forces of attraction between opposite charges and repulsion between similiar charges and that orients an ion in such way where positive ion is surrounded by negative ions and vice versa. They are arranged in such manner that positive and negative charges alternate and balance each other, overall charge of the substance being zero
What is lattice energy
Energy change upon formation of a crystalline ionic compound from its constituent gaseous ions
What does binding in covalent bond arises from
Electrostatic attraction of both nuclei for the same electrons
Some characteristic of covalent bond
It is directional and it gived definitive shapes. It is very strong bond
What is coordinate covalent bond
When both e- come from the same atom
Ex. (H+) + (NH3)=(NH4+)
What is octet rule
Tendency of an atom in a molecule to have 8e- in the valence shell
What does it mean when some element is electron deficient and hypervalent
Electron deficient is when atom in a molecule doesnt have a full octet
And hypervalent is whem it has expanded octet
Why would some molecule be radical
When it has 1 unpaired e-(ex. NO-one e- in N is unpaired,N is e- deficient)
What is electronegativity difference in bonds
In non polar covalent /\X=0
In polar covalent /\X=0.9
In ionic /_\X =2.1
What is bond order
Number of bonds between 2 atoms
•Single bond=two atoms share 1 couple of e-(bond order of 1)
•Multiple bond= the atoms share 2 or more couple of e-
°Double bond-bond order 2
°Triple bond-bond order 3
