(U1) Bonding Flashcards
1
Q
What is a covalent bond? (3)
A
- electrostatic attraction
- between a shared pair of electrons
- and the nuclei of bonded atoms
2
Q
What is a lone pair? (2)
A
- a pair of unshared electrons
- in the outer shell
3
Q
What is a co-ordinate / dative bond? (3)
A
- a shared pair of electrons
- between 2 atoms
- with both electrons shared by 1 atom
4
Q
State the octet rule (3)
A
- when forming a compound
- an atom tends to gain, lose or share electrons
- to achieve 8 in its outer shell and become stable
5
Q
What is electronegativity? (2)
A
- the extent to which an atom attracts bonding electrons
- in a covalent bond
6
Q
What is a polar bond? (2)
A
- a covalent bond
- with unequal sharing of the bonding electrons
7
Q
What are delocalised electrons? (2)
A
- outer electrons
- with no fixed positions and that move freely
8
Q
What is an Ionic bond (3)
And
What does it bond?
A
- electrostatic attraction
- between oppositely charged ions
- formed by electron transfer
- Metals and non-metals
9
Q
How do you represent a dative bond in a diagram?
A
An arrow from the atom donating a lone pair of electrons to the ion
10
Q
What is the most electronegative element?
A
Fluorine
11
Q
What difference value on the Pauling scale results in a:
- pure covalent
- polar covalent
- ionic bond?
A
- 0 = pure
- 0-1.7 = polar
- more than 1.7 = ionic
12
Q
Name 3 contradictions to the octet rule
A
- BeCl2
- BF3
- AlCl3
13
Q
Name an expansion to the octet rule
A
SF6
14
Q
Why does BeCl2 contradict and follow the octet rule? (2)
A
- Be atom has 4 outer shell electrons - doesn’t follow
- Cl atom has 8 outer shell electrons - does follow
15
Q
What factors influence m.p. And b.p.? (3)
A
- atomic radius: increase = decreased m.p./b.p.
- nuclear charge: increase = increased m.p./b.p.
- shielding by inner electrons: increase = decreased m.p./b.p.
