Chapter 5

Question 1

What are the numbers of electrons that can fill the first four shells ?

Answer 1

2, 8, 18, 32

Question 2

Define atomic orbital

Answer 2

a region of space around the nucleus that can hold up to 2 electrons, with opposite spins. Shells are made of atomic orbitals.

Question 3

Define s block element, p block element and d block element

Answer 3

Highest energy electron is :
s electron / p electron / d electron

Question 4

What type of electrons are there in the first shell ?

Answer 4

2 x 1s-electrons
two electrons with same energy levels

Question 5

What type of electrons are there in the second shell ?

Answer 5

2 x 2s-electrons
6 x 2p-electrons
two different energy levels, 8 total electrons

Question 6

What type of electrons are there in the third shell ?

Answer 6

2 x 3s-electrons
6 x 3p-electrons
10 x 3d-electrons
three different energy levels, 18 total electron

Question 7

What type of electrons are there in the fourth shell ?

Answer 7

2 x 4s-electrons
6 x 4p-electrons
10 x 4d-electrons
14 x 4f-electrons
four different energy levels, 32 total electrons

Question 8

What shape is a s orbital

Answer 8

spherical shaped

Question 9

What shape is a p orbital

Answer 9

dumbbell shaped ( figure of 8 sideways )

Question 10

How many orbitals are present in an s, p,d and f subshell ?

Answer 10

1, 3, 5, 7

Question 11

How many electrons can an orbital hold upto ?

Answer 11

2 ( with opposite spins due to being negatively charged and repelling each other )

Question 12

What are the 6 rules by which electrons are arranged in a shell ?

Answer 12

Electrons added one at a time
Lowest available energy level is filled first
Each energy level must be filled before the next one can fill
Each orbital is filled singly before pairing
4s is filled before 3d

Question 13

Which electrons are gained/lost when an atom becomes an ion ?

Answer 13

Electrons in the highest energy level

Question 14

Which electrons are lost when d block elements form ions

Answer 14

They lose the 4s-electrons before the 3d-electrons

Question 15

Why does the 4s orbital fill before the 3d orbital

Answer 15

4s orbital has a lower energy level than 3s orbital

Question 16

Define ionic bonding

Answer 16

The electrostatic attarction between positive ions and negative ions / oppositely charged ions

Question 17

Explanation of the solid structures of giant ionic lattices

Answer 17

Resulting from oppositely charged ions strongly attracted in all directions

Question 18

What state are ionic compounds are room temperature and why ?
Do they have high or low melting points ?

Answer 18

Solids at room temp.
High melting / boiling points.
At room temp there is insufficient energy to overcome electrostatic attractive forces between cations and anions in the giant ionic lattice. High temps required to provide energy needed to overcome these forces.

Question 19

Describe an ionic giant lattice

Answer 19

The regular arrangement of alternating positive and negative ions. Each positive ion is surrounded by negative ions and each negative ion is surrounded by positive ions.

Question 20

What two factors do melting points and boiling points depend on ? Explain the relationship using the factors

Answer 20

Depend on ionic charges and size of ions

Charge on bond increases = Strength of ionic bond increases

Size of ions decrease = strength of ionic bond increases

Question 21

Are ionic compounds soluble ?

Answer 21

Yes they dissolve in many polar solvents eg water

Question 22

Electrical conductivity of ionic compounds. Solid vs Liquid/Aqueous states

Answer 22

Solid :
ions held in fixed positions in giant ionic lattice
no mobile charge carriers
no electrical conductivity
non conductors
Liquid/Aqueous :
ions free to move
ions are mobile charge carriers
electricity is conducted

Question 23

Define covalent bond

Answer 23

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

Question 24

What is a dative covalent bond ?

Answer 24

shared pair of electrons and both electrons are donated by one atom

Question 25

What is the average bond enthalpy ?

Answer 25

it is a measurement of covalent bond strength. The energy required to break a covalent bond. The stronger the bond, the more energy is required to break the bond, so the greater the value of the average bond enthalpy.

Question 26

Covalent compound properties ( usually )

Answer 26

low melting and boiling points
soluble in non polar solvent eg hexane ( not water )
poor conductors of electricity even when molten

Question 27

How to decide whether something is ionic or covalent

Answer 27

know electrons in outer shell
use dots and crosses ( and then maybe triangles )
unless it’s an exception, make sure each atom ends up with 8 outer shell electrons
for elements lower down, copy element at top of group
exceptions are BeCl2, BF3, SF6

Question 28

What are the three main exceptions to the rules of ionic and covalent bonding ?

Answer 28

BeCl2, BF3, SF6

Question 29

When can expansion of the octet occur ?

Answer 29

only possible when n = 3 when a d sub shell becomes available.

Question 30

What is the octet rule ?

Answer 30

Outer shell has octet ( 8 ) of electrons
Most stable arrangement for any atom
Arrangement causes unreactivity
No more electrons required to complete outer shell