Chapter 5: Electron and bonding (5.1-5.3)

Question 1

What are the maximum number of electrons in the first four shells?

Answer 1

1st shell = 2, 2nd shell= 8, 3rd shell = 18, 4th shell = 32 (Use the formula 2n^2 to find the maximum number of electrons)

Question 2

What are the four types of atomic orbitals?

Answer 2

s-, p-, d-, f-

Question 3

What are the four features of an s- orbital?

Answer 3

• It can hold one or two electrons
• Each shell from n=1 contains one s-orbital
• The greater the shell number n, the greater the radius of its s-orbital
• It has a spherical shape (draw a circle)

Question 4

What are the four features of an p-orbital?

Answer 4

• There are 3 separate p-orbitals at right angles to one another (px, py, pz)
• Each shell from n=2 contains 3 p-orbitals
• The greater the shell number n, the further the p-orbital is from the nucleus
• It has a shape like a bar bell

Question 5

what shells contain d-orbitals?

Answer 5

Each shell from n = 3 contains 5 d-orbitals

Question 6

what shells contain f-orbitals?

Answer 6

Each shell from n = 4 contains 7 f-orbitals

Question 7

Maximum number of electrons in orbitals s-, p-, d-, f-

Answer 7

S = 2, P = 6, D = 10, F = 14

Question 8

What are the two rules of how electrons fill sub-shells?

Answer 8

• Electrons in the same sub-shell fill up orbitals singly before pairing
• Orbitals fill in order of increasing energy (e.g in the n = 2 shell the order is 2s, 2p)

Question 9

What is the anomaly of how electrons fill sub-shells and how does this effect how you write electronic configurations of elements and ions?

Answer 9

The 3d sub-shell is at a higher energy than the 4s sub-shell. This means that the 4s sub shell fills before the 3d sub shell and also loses electrons before the 3d sub-shell, therefore the order of filling is 3p, 4s, 3d.

Question 10

How would you write the electronic configuration of Krypton (Z=36)?

Answer 10

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6

Question 11

Why does the 4s shell also lose electrons before the 3d sub-shell?

Answer 11

The energies of the 4s and 3d sub-shells are very close together. Once filled the 3d energy level falls below the 4s.

Question 12

How do you classify elements into different blocks?

Answer 12

Their blocks corresponds to their highest energy sub-shell meaning there can be 4 blocks (s, p, d, f)

Question 13

What is ionic bonding?

Answer 13

The electrostatic force of attraction between positive and negative ions

Question 14

Melting and boiling point of ionic substances

Answer 14

High temperatures are required to supply the energy needed to overcome the strong electrostatic force of attraction. Therefore ionic compounds have high melting points.

Question 15

What does the melting point in ionic lattices depend on?

Answer 15

Melting points are higher for lattices containing ions with greater ionic charges and ionic attraction also depends on the size of the ions.

Question 16

Solubility of ionic compounds

Answer 16

They dissolve in polar solvents (e.g water) as these break down the lattice and surround each ion in solution.

Question 17

What does the solubility of ionic compounds depend on?

Answer 17

The charges in the lattice - they may be too strong for water to break down the lattice. Therefore it depends on the attraction between ions and water molecules and the relative strength of attraction within the lattice.

Question 18

Electrical conductivity of ionic compounds

Answer 18

In solid state ionic compounds do not conduct electricity because the ions are in fixed positions in the giant ionic lattice and there are no mobile charge carriers. However, in the liquid or aqueous state the solid ionic lattice breaks down and the ions are free to move as charge carriers.

Question 19

What is covalent bonding?

Answer 19

The strong electrostatic force of attraction between a shared pair of electrons and the nuclei of the bonded atoms.

Question 20

How is an ionic bond different to a covalent bond ?

Answer 20

Ionic bonding is the loss and gain of electrons whereas a covalent bond is sharing electrons. Also, ions attract oppositely charged ions in all directions whereas a covalent bond is localised

Question 21

What can chlorine do due to it having 7 unpaired electrons?

Answer 21

It could form ClF7 meaning that the outer shell would have 14 electrons and chlorine’s n=3 shell can hold 18 electrons (this happens due to the d-sub-shell becoming available for expansion)

Question 22

What is a dative covalent bond?

Answer 22

A shared pair of electrons in which the bonded pair has been supplied by one atom only (e.g. NH4)

Question 23

What is a simple molecular lattice?

Answer 23

Its where molecules are held in place by weak intermolecular forces but the atoms within each molecule are bonded together strongly by covalent bonds.

Question 24

Why do simple molecular substances have low melting and boiling points?

Answer 24

The weak intermolecular forces of attraction do not take much energy to overcome and the covalent bonds do not need to be broken.

Question 25

Describe the solubility of a non-polar simple molecular substance in a non-polar solvent

Answer 25

When it is added intermolecular forces fork between the molecules and the solvent and the interactions weaken the intermolecular forces in the simple molecular lattice and the forces break, so the compound dissolves.

Question 26

Describe the solubility of a non-polar simple molecular substance in a polar solvent

Answer 26

When it is added there is little interaction between the molecules in the lattice and the solvent molecules so the intermolecular bonding within the polar substance is too strong to be broken.

Question 27

Describe the solubility of polar simple molecular substances in a polar solvent

Answer 27

Polar covalent substances may dissolve in polar solvents. If they have polar bonds this can attract and bond with polar molecules but the solubility depends on the strength of the dipole.

Question 28

Describe electrical conductivity in simple molecular substances

Answer 28

There are no mobile charged particles in simple molecular structures, with no charged particles that can move, they cannot conduct electricity

Question 29

multiple covalent bonds

Answer 29

can only be done by non-metals
atoms sharing more than one pair of electrons
represented in displayed formula by multiple lines between atoms

Question 30

strength of multiple covalent bonds

Answer 30

more covalent bonds = stronger

Question 31

types of covalent structure

Answer 31

simple molecular
giant covalent lattice
graphene