Chemical bonds!

Question 1

What is the difference in electronegativity needed for a bond to be ionic?

Answer 1

ΔEN > 1.7

Question 2

What is the difference in electronegativity needed for a covalent bond?

Answer 2

ΔEN < 1.7

Question 3

Below what electronegativity difference is a colavent bond not considered polar?

Answer 3

ΔEN < 0.4

Question 4

What electronegativity must an element be below to be able to for metallic bonds?

Answer 4

Below 2

This means they don’t strongly attract or repel e-, therefore they are better suited to metallic bonding

Question 5

What forces holds crystal lattices together?

Answer 5

Electrostatic forces (this just means attraction between + and -)

Question 6

What repels ligands more - a bonding pair of electrons or a lone pair of electrons?

Answer 6

Lone pair

Question 7

What p orbitals would a single-bonded carbon have?

Answer 7

4x p orbitals

Question 8

What p orbitals would a double-bonded carbon have?

Answer 8

1x sp orbital
3x p orbital

1x sigma pp bond + 1x pi sp bond = double bond

Question 9

What p orbitals would a triple-bonded carbon have?

Answer 9

2x sp orbital
2x p orbital

1x sigma pp bond + 2x pi sp bonds = triple bond

Question 10

What is the process of promoting carbon electrons to a higher energy level to form 4 bonds known as?

Answer 10

Hybridisation

Question 11

How many bonds will oxygen always make?

Answer 11

2

Question 12

How many bonds will hydrogen and fluorine always make?

Answer 12

1

Question 13

What is a dative/coordinate bond?

Answer 13

Both electrons in the shared pair are donated by the same atom

Question 14

What is the Pauli exclusion principle?

Answer 14

no two electrons can have the same set of quantum numbers

Question 15

What are polyatomic anions?

Answer 15

Polyatomic anions are negatively charged ions composed of two or more atoms covalently bonded, acting as a single unit with an overall charge - name changes depending on the amount of oxygen the compound contains

Question 16

Does a covalent bond have a specific length?

Answer 16

Yes but it is not stiff, the energy is simply at the lowest when it is at its correct length

Question 17

What does VSEPR theory dictate?

Answer 17

VSEPR theory is a model used to predict the shape of molecules based on the idea that electron pairs around a central atom repel each other and will arrange themselves as far apart as possible to minimize repulsion
Valence Shell Electron Pair Repulsion

Question 18

How do you decide spatial structure using VSEPR theory?

Answer 18

Count number of binding electron pairs and free electron pairs
Achieving maximal distance between pairs determines shape

Question 19

Use VSEPR on carbon

Answer 19

Question 20

What does valence bond theory state?

Answer 20

Valence Bond Theory (VBT) is a model used to explain how atoms form covalent bonds by the overlap of atomic orbitals and sharing of electrons

Question 21

What bonds make up a double bond?

Answer 21

1 sigma
1Pi

Question 22

What bonds make up a triple bond?

Answer 22

1 sigma
2 Pi

Question 23

This fc has a table showing electron groups and hybridisations with the expected shapes. Try remember the first 2 - i.e. sp, sp2

Answer 23

Basically to remember:
sp has 2 groups because s+p
sp2 has 3 electron groups because s+p+p and so on
Then use the shape mnemonic
sp -> linear
sp2 -> trigonal planar
sp3-> tetrahedral
Then from 4 groups, you add an increasing amount of d
sp3d -> 5 groups -> Trigonal bipyramidal
sp3d2 -> 6 groups -> octahedral