Lecture 5&6- Bonding And Lewis Structure Flashcards
What are the three main types of bonding?
Ionic, Covalent, Metallic
These types of bonding describe how atoms interact to form molecules.
Define a molecule.
A neutral entity consisting of two or more atoms held together by chemical bonds
Most often these bonds are covalent.
What is the difference between a compound and a molecule?
All compounds are molecules but not all molecules are compounds. Compounds must contain different elements, whereas molecules can contain atoms of the same element
Example: O2 is a molecule, but H2O is a compound.
What are the components of an atom?
Nucleus (protons + neutrons), Electrons (surround the nucleus)
Electrons play a principal role in chemical bonding.
Why do atoms bond together?
To form a compound that is more stable (has less energy) than the separate atoms
Chemical bonds lower the potential energy between charged particles.
What are valence electrons?
Electrons in the outer shell associated with an atom, which can participate in the formation of a chemical bond
Valence electrons are critical for bonding.
What is the Octet Rule?
Atoms will gain or lose electrons to achieve the noble gas configuration
The rule applies to elements with valence electrons in the s- and/or p-orbitals.
Which elements commonly follow the Octet Rule?
Elements whose valence electrons are in the s- and/or p-orbitals
Does not apply to transition metals or d-block elements.
What is valency?
The combining power of an element, related to the number of electrons in the outer shell
Valency is used to predict the formulae of simple compounds.
What does univalent mean?
Having a valency of one
Example: H in H2O.
What does divalent mean?
Having a valency of two
Example: O in H2O.
What is the relationship between valency and oxidation number?
Valency relates to the number of bonds formed, while oxidation number indicates the charge after losing or gaining electrons
Valency has no sign.
Describe ionic bonds.
Electrostatic attraction between atoms of opposite charges
Ions form from the complete transfer of electrons.
Describe covalent bonds.
Result from the sharing of electrons between two atoms
Common in non-metallic elements.
Describe metallic bonds.
Metal atoms bonded to several other atoms with delocalised electrons
Responsible for the lustre and high electrical conductivity of metals.
What is electronegativity?
The ability of an atom to attract a shared pair of electrons in its combined state
It determines how atoms bond with each other.
What is electropositivity?
The ability of an atom to withdraw a shared pair of electrons in its combined state
This property contrasts with electronegativity.
What is the significance of Lewis structures?
Representations of molecules showing all electrons - bonding and nonbonding
They help visualize electron sharing and lone pairs.
What does OIL RIG stand for?
Oxidation Is Loss / Reduction Is Gain
A mnemonic to remember the principles of oxidation and reduction.
How do you draw a Lewis structure?
- Find the sum of valence electrons. 2. Write symbols for atoms and connect with single bonds. 3. Complete octets around bonded atoms. 4. Place leftover electrons on the central atom.
If central atom lacks an octet, try multiple bonds.
What is a double bond in Lewis structures?
When two electron pairs are shared, represented by two lines
Example: O=C=O for carbon dioxide.
What is a triple bond in Lewis structures?
When three electron pairs are shared, represented by three lines
Example: N≡N for nitrogen gas.
What are lone pairs?
Pairs of electrons that are not shared with other atoms
They can influence molecular shape and reactivity.
What is the role of molecular shape in reactivity?
The shape of a molecule plays an important role in its reactivity
It affects how molecules interact with each other.
