Unit 6 (Ionic and Covalent Bonding) Flashcards
What are the two types of bonding?
1. explain ionic
2. explain covalent
Ionic - Involves a transfer of electrons. One element loses electrons and the other gains electrons.
Covalent - involves a sharing of electrons. Atoms will share in order to reach a stable electron configuration.
What is the Octet Rule?
1. definition
2. 4 exceptions
atoms will gain or lose enough electrons to become isoelectronic with a noble gas
Except for: hydrogen helium lithium beryllium
Electron (Lewis) Dot Structures
1. what are they?
2. How do they have to be labeled?
3. what can # of valence electrons be determined by? 2 blocks they come from
A way to show the number of valence electrons in an atom
should be labled similar to this pattern:
———6—–2———
3———————–1
———-X—————-
7———————–5
———4—-8———-
The number of valence electrons can be determined by the group the elements are in. These come from the s and p blocks only!
Fill in these charts
1. Group # 1, 2, 13, 14, 15, 16, 17, 18. Valence Electrons. Electron Dot Structure
2. Elements in the same group behave ….. ???
3. Group # 1, 2, 13, 14, 15, 16, 17, 18. Electron Activity. Charge
1, 2, 3, 4, 5, 6, 7, 8
Li, Be, B, C, N, O, F, Ne
Valence electrons determine chemical reactivity - elements in the same group behave the same
lose 1, lose 2, lose 3, not involved, gain 3, gain 2, gain 1, happy
+1, +2, +3, not involved, -3, -2, -1, happy
Ionic Bonding
1. what it forms from
2. the thing it is made up of.
3. Formula unit, pattern descriptions
4. melting points, and conductivity
remember how to do electron configurations for ions
Forms from attraction between + and - ions
An ionic compound is made up of crystals/crystal lattices.
* A crystal consists of a 3D, repeating pattern of alternating + and - ions.
* Formula unit: the lowest whole number ratio of ions
Ionic compounds have high melting points
conduct electricity when melted (molten) or dissolved in water
Example: NaCl
Ionic bonds quick facts run down
1. strength
2. room temp state
3. melting/boiling points
4. metallic made up
5. conductivity
6. aqueous definition
- very strong
- are solids at room temperature
- have high melting and boiling points
- made up of a metal and nonmetals
- does not conduct electricity in solid state, but does in the liquid (molten) and aqueous states
- aqueous - dissolved in water
Formation of Ionic compounds example
Do you remember how to do the diagrams to predict the compound that would form between two elements??
Hope so
Remember the solutions
1. draw arrows pointing to the missing valence electron positions
2. sometimes you need multiple elements
3. Remember its LOWEST ratio
4. You need to lose every electron for the left element
5. In the molecular formula, METALS go first
Final element example H2 S
https://homework.study.com/explanation/how-do-you-predict-the-formulas-for-ionic-compounds-using-the-electron-dot-structures.html
Empirical Formulas
1. description
2. examples of empirical vs not empiricial
The chemical formula for an ionic compound is arranged in the smallest whole-number ratio is known as an empirical formula.
Empirical - Mg3N2 vs
not empirical - Mg6N4
Colvanet bonding SUPER rundown
1. what is it in 4 words?
2. what is it made of?
3. what happens
4. what does it occur between
5. what are covalently bonded atoms called
6. are they weaker or stronger than ionic bonds
7. melting and boiling points
8. state(s) at room temperature
9. conductivity?
10. name for the chemical formula (+ what does this indiciate)
A sharing of electrons.
A single covalent bond is made up of two electrons
One electron is donated to the bond from each atom
Covalent bonding occurs between non metals only.
Atoms that are covalently bonded are called molecules or moleculer compounds.
Covalent bonds are much weaker than ionic bonds.
Much lower melting and boiling points
Is a solid, liquid, or gas at room temperature.
Non conductors in any state
The chemical formula for a covalently bonded group of atoms is called a molecular formula.
* Indicates the exact makeup of one molecule instead of the ratio
The # of electrons short is the number of bonds that can be made. So group 1 has 1 possible bond, group 15 has 3, group 17 has 1, get it?
I hope so
Do you know how to do structural (lewis) formulas, electron dot formulas, and rough copy (work!)??
single bonds, double bonds, triple bonds
I hope so. Again, review the worksheets to see examples
Rough copy - connected dots
Electron dot - just dots, no circle
Structural - lines, 1 for a single bond, 2 for double, 3 for triple bond.
single - one shared pair of 2 electrons
double bonds - two shared pairs of 4 electrons
triple bonds - three shared pairs of 6 electrons
tip - put the atom in the middle that must make the most bonds
Explain the Valence Shell Electron Pair Repulsion Theory (VSEPR)
* what does it say?
* what this determines
says that the electron pairs (both shared and unshared) in the outermost energy level try to get as far apart from each other as possible
this determines the shape of the molecules
Explain the 6 shapes of molecules and their
* example(s)
* # of atoms
* shape
* required # of unshared pairs for the central atom
Trigonal Bipyramidal has 3 angles, so can you name what the special rule for it is??
Linear
* example H — H and O = C = O
* 2 or 3 atoms
* 180 degree angle
* NO unshared pairs
Bent
* example H2O
* 3 atoms
* about a 104.5 degree angle
* can have one or two unshared pairs
Trigonal Planar
* example CH2O
* 4 atoms
* about 120 degrees
* NO unshared pairs
Pyramid
* example NH3
* 4 atoms
* 107.5 degrees
* ONE unshared pair
Tetrahedral
* example CH4
* 5 atoms
* 109.5 degrees
* NO unshared pairs
Trigonal Bipyramidal
* example: PF5
* 6 atoms
* 90, 120, and 180 degrees
* for elements in period 3 and higher, when bonded to Cl or F, will have an expanded octet
* NO unshared pairs
What is a polar bond?
1. defintion. Bonds where…
2. What happens to atoms that are electronegative?
3. What happens to electrons when atoms are different?
4. Example:
Polar bond: bonds where the electrons are shared unequally between atoms
The atom that is electronegative will pull the electrons closer to itself
When atoms are different, each has a different pull on the electrons
H —- F. Shared electrons are closer to fluorine because it is more electronegative.
Explain Nonpolar bonds
1. definition
2. atoms that are the same have what ??
3. examples - will be given
Non polar bonds: Electrons are shared equally between two atoms
Atoms that are the same have the same pull on the shared electrons same E.N. value
Example: H2 H — H Both atoms have the same E.N. value
Example: CCl4 ALL atoms surrounding carbon are the same, therefore all electrons are shared equally
