2.5 Electrons, Bonding and Structure

Question 1

What is the principal quantum number ?

Answer 1

Number representing the overall energy of each orbital, which increases with distance from the nucleus.

Question 2

What is the main energy level ?

Answer 2

Also known as the shell. It is a group of atomic orbitals with the same principal quantum number.

Question 3

What is an atomic orbital ?

Answer 3

Volume of space that can contain up to 2 electrons of the opposite spin.

Question 4

How many electrons can occupy the first energy level ?

Answer 4

2 electrons maximum.

Question 5

How many electrons can occupy the second energy shell ?

Answer 5

18 electrons maximum.

Question 6

How many electrons can occupy the 4th energy level ?

Answer 6

32 electrons maximum.

Question 7

How many electrons can occupy the 5th energy level ?

Answer 7

50 electrons maximum.

Question 8

What are s-orbitals ?

Answer 8

S-orbitals are spherical around the nucleus of an atom. They can contain 2 electrons maximum. Each energy level has an s-orbitals.

Question 9

What are p-orbitals ?

Answer 9

P-orbitals are a dumb-bell shape with the nucleus in the middle. Can contain 6 electrons maximum. There are no p orbitals in the first energy level.

Question 10

What are d orbitals ?

Answer 10

D-orbitals occupy a flower shape around the nucleus. Can contain 10 electrons maximum (5[] x2).

Question 11

What sub-shell has the lowest energy ?

Answer 11

1s has the lowest energy and therefore, gets filled first.

Question 12

What do opposite spins help to do ?

Answer 12

Help to counteract repulsion between negative charges of 2 electrons. 2 electrons in an orbital must have opposite spins.

Question 13

What do blocks in periodic table correspond to ?

Answer 13

Blocks correspond to their highest sub-shell energy.

Question 14

What is the s-block ?

Answer 14

S-blocks highest energy electrons are in the s-sub shell (left block of the 2 groups).

Question 15

What is the p-block ?

Answer 15

P-blocks highest energy electrons are in the p-sub shell (right block of the 6 groups).

Question 16

What is the d-block ?

Answer 16

D-blocks highest energy electrons are in the d-sub shell (centre block of the 10 groups).

Question 17

When forming ions, what do the highest energy sub-shells do ?

Answer 17

When forming ions, the highest energy sub-shells lose or gain electrons in the s-block or p-block orbitals.

Question 18

What happens to d-block when forming ions ?

Answer 18

For d-block elements, the 4s sub-shell is at a lower energy than the 3d sub shell, so is filled first. The energies of the two are close together and once filled the 3d sub-shell falls below the 4s sub-shell.

Question 19

What is ionic bonding ?

Answer 19

Electrostatic attraction between positive and negative ions in ionic compounds.

Question 20

What do the simplest ionic compounds contain ?

Answer 20

Simplest ionic compounds contain metal and non-metal ions.

Question 21

What is the structure of ionic compounds ?

Answer 21

Each ions attract oppositely charged ions in all directions. This results in a giant ionic lattice containing billions of ions.

Question 22

What can the physical properties be explained by ?

Answer 22

Physical properties can be explained by lattice structure and ionic bonding.

Question 23

What is the melting and boiling point of ionic compounds ?

Answer 23

Almost all ionic compounds are solid at room temperature, as there is insufficient energy to overcome the strong electrostatic attraction between oppositely charged ions in a lattice.

Question 24

What is the solubility of ionic compound ?

Answer 24

Many ionic compounds dissolve in polar solvents, such as water. Polar water molecules break down the lattice and surround each ion in the solution.

Question 25

What is the solubility in compounds of ions with a large charge ?

Answer 25

In compounds with ions of a large charge, the ionic attraction may be too strong for polar solvents to break down the lattice structure. The compound will then not be very soluble.

Question 26

Can ionic compounds conduct electricity in a solid state ?

Answer 26

In a solid state, an ionic compound does not conduct electricity.

Question 27

Can ionic compounds conduct electricity melted or dissolved in water ?

Answer 27

Yes, ionic compounds can conduct electricity in a liquid sate or aqueous solution.

Question 28

Structure of ionic lattice in a solid state

Answer 28

-Ions are in a fixed position.
-No mobile charge carriers.
-No conductivity.
-Cannot move.

Question 29

Structure of ionic lattice in dissolved state

Answer 29

-Solid lactic breaks down.
-Ions are free to move.
-Can conduct electricity.

Question 30

What is covalent bonding ?

Answer 30

Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.

Question 31

What is an orbital overlap ?

Answer 31

Covalent bonding is the overlap of atomic orbitals forming a sigma bond.

Question 32

What does it mean when the attraction is localised and what does it result in ?

Answer 32

Attraction is localised, solely between the shared pair of electrons and the nuclei of 2 bonded atoms. Results in a molecule, which is the smallest part of a covalent bond that still retains properties of a covalent compound.

Question 33

What are dot and cross diagrams ?

Answer 33

Show the sharing of electrons from different atoms and electrons min the outer shell of an atom.

Question 34

When do multiple covalent bonds exist ?

Answer 34

Exist when atoms share more than one pair of electrons between atoms. Double covalent bond is the sharing of 2 pairs of electrons. Triple covalent bond is the sharing between 3 pairs of electrons.

Question 35

Why does boron form an unusual covalent bond ?

Answer 35

BF3 has three electrons in outer shell and shares all 3, meaning only has 6 electrons total in the outer shell. This shows that predictions for bonding cannot base solely on noble gas electron structure.

Question 36

Why does sulfur form an unusual covalent bond ?

Answer 36

SF4 has 4 electrons in sulfur that bond to 4 fluorine leaving a lone pair of electrons. This means sulfer has 10 electrons in the outer shell.

Question 37

What is a dative covalent bond ?

Answer 37

Shared pair of electrons, where both electrons come from the same atom.