Chemical Bonding Part 1 Flashcards
Give the two reasons atoms bond and why? (2x3)
- To obtain noble gas electron structures
Want the outer most energy levels to be full = increase in stability and no more chemical bonding
- To obtain a lower state of energy
Energy is released to form chemical bonds.
Formations allow atoms to achieve a lower energy level
What is Chemical Bonding (3)
Chemical bonding is the process by which atoms bond with each other and in this way achieve a noble gas configuration, with low potential energy
What is a molecule? (2)
A molecule is a group of two or more atoms which are bonded together strongly enough to behave as a single unit in a chemical reaction
A bonded state is known to be? (1)
A non bonded state is also known as… (1)
- More stable state
- “free state”not stable
What are between chemical bonds? (3) #
- Must be forces to form such a unit
- A mutual binding force = chemical bonding
- Both attractive and repulsive forces between the atoms
Two ways atoms attract to each other (2) #
- Nucleus (+) with its own electrons (-)
- Nucleus (+) with other atoms electrons (-)
2 ways the atoms repel (2) #
- Nucleus (+) with other nucleus (+)
- Electrons (-) with other electrons (-)
How do bonds form? (1) #
When forces of attraction = forces of repulsion
What is bond length? (2) #
- The distance between the nuclei of the atoms
- The lowest energy point, where the atoms want to be
How does energy change in an atom? (2) #
Attraction - work more over a long distance
Repulsion - work more over a short distance
Point at which atoms are far apart is taken advantage? (1) #
0
What is bond strength? (2) #
Bond strength is the amount of energy needed to break a chemical bond
Bond strength and length are… (1) #
- Inversely related
Bond strength points (3) #
- measured in joules
- weak bonds easily broken
- strong bonds hard to break
Decimeter (2) #
- dm
- 10^-1m
Centimeter (2) #
- cm
- 10^-2m
Millimeter (2) #
- mm
- 10^-3m
Micrometer (2) #
- um (curved u)
- 10^-6m
Nanometer (2) #
- mm
- 10^-9m
Picometer (2) #
- pm
- 10^-12m
What is valency? (2)
Valency is the measure of the number of chemical bonds formed by the atoms of a given element
Calculating valency: Groups 1-4 = Groups 5-8 = Charge of ion = Roman numerals = Zinc = Silver =
= group number = 8 - group number = valency = valency = 2 = 1
What group is the exception to the Lewis structure? (1)
Group 4 (1 on each side)
- Carbon
- Silicon
Elements don’t gain electrons to become noble gases. They… (1)
They gain noble gas electron STRUCTURES
Atoms can gain noble electron structures in 3 ways (3)
- Share electrons
- Gain electrons
- Donate electrons
3 types of bonding (3)
- Covalent
- Metallic
- Ionic
What is Covalent bonding? (2)
Covalent bonding is a sharing of electrons between two non-metal atoms, forming a molecule
4 points on a covalent bond (4)
- Generally occurs between 2 non-metals
- It is the sharing of electron pairs
- Product is called a molecule
- Shared pair of electrons = bonding pair
Unshared pairs of valence electrons are known as…
Lone pairs
Each electron must have opposition spin
What is Electronegativity? (2)
Electronegativity is an indication of the attraction that an atom exerts on a shared electron pair
What is the bonding force?
The coulombic attraction between the nuclei (+) and the electrons (-)
Why does Helium not form He2? (1)
Because it is already a noble gas with a filled up valence electron structure
Why do noble gases not have Electronegativity? (1)
They don’t share electron pairs because they don’t bond
Fluorine has the highest Electronegativity. Why? (1)
It has a very strong attraction for a shared electron pair
What is a non polar covalent bond? (2)
A non polar covalent bond (pure covalent bond) is a covalent bond where there is an equal sharing of electrons
What is a polar covalent bond? (2)
A polar covalent bond is a covalent bond where there is an unequal sharing of electrons leading to a dipole forming (as a result of Electronegativity difference)
Delta means what (3)
- a change in something
- bigger delta shown as a triangle
- small shown as an sd
Explain the difference in Electronegativity? (3)
When the electronegativity is 0 = Non Polar Covalent Bond
When bigger than 0 but smaller than 2,1 = Polar Covalent Bond
When bigger than 2,1 = Ionic Bond
What is a dipole? (1)
A dipole is the separation between two covalently bonded atoms
Give me an example of dipoles (2)
- HCl
- H has a lower Electronegativity so it gets the - delta
- Visa Versa
What is the polarity of a bond? (3)
- The bond dipole
- Indicated by an arrow
- Points towards more electronegative side
