Chemical Bonding Flashcards
What group is the Nobel gases in?
Group 8
What are the 6 Nobel gases?
- He
- Ne
- Ar
- Kr
- Xe
- Rn
How many electrons do Nobel gases have in there outer electron?
8
Describe novel gases:
- Very stable and un-reactive or inert
- Monatomic
- Dont normally form bonds with other elements
- Do not need to gain, lose or share electrons
- Lewis Octet rule
What does monatomic mean?
They exist as individual atoms
What are valance shells?
- Outermost occupied shell of an atom
- Highest principle quantum number
- Most likely to participate in bonding
What will atoms without 8 electrons in the valence shells will form?
Chemical bonds with other atoms
What are chemical bonds made from?
Electrons
How do atoms make bonds?
Atoms must collide with each other to make bonds
What are the two types of electrons in an atom?
- Core electrons
- Valance electrons
Define ionic bonds:
Is the electrostatic attraction that forms between oppositely charged ions
What two main ways for atoms bond with other bonds?
- Ionic bonding
- Covalent bonding
Define covalent bond:
is a shared pair of electrons between atoms
What happens between atoms in ionic bonding?
- Atoms gain or loss electrons to fulfil the octet rule
- Atoms become ions
Atoms that lose electrons have more or less proton than electrons?
More
Atoms that gain electrons have more or less protons to electrons?
Less
Do atoms become positively or negatively charged when they lose electrons?
Positive
Do atoms become positively or negatively charged when they gain electrons?
Negative
What are atoms called when they lose electrons?
cations
What elements normally lose electrons?
S and d block elements
What aerators called when they gain electrons?
Anions
What elements normally gain electrons?
P block elements
What charge do ionic compounds have?
Neutral charge
If ionic compounds have a neutral charge what must the total of cations equal to the total of anions?
Cations and anions must be equal
What are ionic lattices?
Ionic compounds form giant 3D structures
What are diatomic?
Two atoms joined tother by a covalent bond
Give an example of diatomics:
Fluorine
Chlorine
Oxygen
Nitrogen
Describe Fluorine:
- 9F so 1s2, 2s2, 2p5
- F atom requires 1 electron for full valence shell
- Forms diatomic fluorine molecule, F2
- Single F-F bond
Describe chlorine:
- 17Cl so 1s2, 2s2, 2p6, 3s2, 3p5
- Cl atom requires 1 electron for full valence shell
- Forms diatomic chlorine molecule,Cl2
- Single Cl-Cl bond
Describe oxygen:
- 8O so 1s2, 2s2, 2p4
- O atom requires 2 electrons for full valence shell
- Forms diatomic oxygen molecule, O2
- Double O=O bond
Describe nitrogen:
- 7O so 1s2, 2s2, 2p3
- N atom requires 3 electrons for full valence shell
- Forms diatomic oxygen molecule, N2
- Triple N≡N bond
How can covalent bonds be represented by?
By lines or wedges
What determines whether the bond is ionic or covalent?
Electronegativity
What is electronegativity?
Ability of an atom to pull electrons towards itself
Finish the sentence:
An atom with a high electronegativity pulls electrons…
more strongly towards itself
In which direction does does electronegativity increase on the period table?
- horizontally left to right
- vertically down to up
What is the Pauling scale of electronegativity?
Increase electronegativity across the periodic table
What does electronegativity depend on?
- Nuclear charge
- Atomic radius
- Electron shielding
What does an atom need to have high electronegativity?
- Higher nuclear charge
- Small atomic radius
- Low amount of shielding
If the difference in values of electronegativity is greater than 1.7 is it more likely to form covalent or ionic bonds?
Ionic bonds
If the difference in values of electronegativity is less than 1.7 is it more likely to form covalent or ionic bonds?
Covalent bonds
If the difference in values of electronegativity is equal to 1.7 what bond is it more likely to form?
Polar covalent bond
Why is hydrogen chloride a special case?
- Gaseous form are polar covalently bonded
- Aqueous form ionises completely to give cation and anions
- Electronegativity difference is 0.9
What electronegativity differences do covalent bonds have?
0.0
What electronegativity differences does polar covalent bonds have?
0.9
What electronegativity differences does ionic bonds have?
2.1
What differences do compounds with ionic bonds have compared to covalent bonds?
- Boiling point
- Melting point
- Solubility in water
- Electrical conductivity
What charge does phosphate ion have?
-3
What charge does sulphate ion have?
-2
What charge does carbonate ion have?
-2
What charge does nitrate ion have?
-1
What charge does hydroxide ion have?
-1
What charge does ammonium have?
+1
Is hydrogen sulphate an acid or base?
Acid
Is hydrogen nitrate an acid or base?
Hydrogen nitrate
Is sodium carbonate an acid or base?
base
Is sodium hydroxide an acid or base?
base
Do all electrons in covalent bonds need to bonded?
No
What are lone pairs?
Unbonded pairs of electrons
What are dative covalent bonds?
Lone pairs can be shared with ions