Electrons and Bonding

Question 1

What can shells be regarded as?

Answer 1

Energy levels

Question 2

What does the principal quantum number n indicate ?

Answer 2

The shell that the electrons are in eg shell 4 = 4

Question 3

Fill in the gaps . The larger the value of n (principal quantum number ) the further the shells is from the ….. and the ……. The energy level

Answer 3

Nucleus and higher

Question 4

How many electrons can be in shell 1 , 2 , 3 ,4

Answer 4

2 ,8,18,32

Question 5

What is an atomic orbital

Answer 5

An atomic orbital is a region around the nucleus that can hold up to two electrons , with opposite spins

Question 6

What is a subshell

Answer 6

A subshell is all of the orbitals of the same type in the same shell

Question 7

What are the four different types of orbitals

Answer 7

S , p , d and f

Question 8

What shape is an s orbital

Answer 8

Spherical

Question 9

What shells contain p orbitals (3)

Answer 9

2 onwards

Question 10

What shells contain 5 d orbitals

Answer 10

3 onwards

Question 11

What shells contain f orbitals (7)

Answer 11

4 onwards

Question 12

What is principal quantum number?

Answer 12

N is a number representing the relative overall energy of each orbital which increases with distance from the nucleus. The sets of orbitals with the same n value are referred to as electron shells or e energy levels

Question 13

Which orbital fills up first? 4s or 3d

Answer 13

4s

Question 14

What does the Pauli exclusion principle state

Answer 14

No more than 2 electrons can occupy any orbital and this is because of electron spin . Two electrons occupying the same orbital must have opposite

Question 15

What do the opposite spins counteract

Answer 15

The repulsion between the negative charges ( electrons are negative )

Question 16

what elements go against the shells rules and why

Answer 16

copper and cromium are the exceptions so they have increased stability and lower energy

Question 17

what is the electron configuration for cromium
(cr) exception

Answer 17

1s2 , 2s2,2p6,3s2,3p6,4s1,3d5.

Question 18

what is the electron configuration for copper (exception)

Answer 18

1s2,2s2,2p6,3s2,3p6,4s1,3d10

Question 19

when writing the electron configurations for ions which electrons go first , 3d or 4s

Answer 19

4s , electrons are lost first (remember first in first out )

Question 20

what state are most ionic substances at room temp

Answer 20

solid , this is because high temperatures are needed to provide enough energy to overcome the strong electrostatic attraction between the ions

Question 21

what does the melting point of ionic compounds depend on

Answer 21

the size of the ionic charge and the size of the ion (ionic radius , whicn can be found in a data book)

Question 22

what is a giant ionic lattice

Answer 22

a regular repeating pattern which is caused as every ion in the structure attracts opposittely charged ions in all directions

Question 23

why do ionic compounds conduct when molten or dissolved in water

Answer 23

because the solid ionic lattice breaks down. and the ions are free to move as mobile charge carries

Question 24

what solvents do ionic compounds dissolve in ? and why

Answer 24

many ionic compounds dissolve in polar solvents . this is because polar molecules break down the lattice and surround each ion in solution

Question 25

why can some polar solvents not dissolve the ions

Answer 25

for a compound with a large ionic charge , the ionic attraction may be too strong for water to be able to break down the lattice

Question 26

what does solubility depend on?

Answer 26

solubility depends on the strength of the attraction between the ions , and the attraction between the ions and the water molecules

Question 28

P orbitals have equal energy

Question 29

What is a covalent bond

Answer 29

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

Question 30

Molecule definition

Answer 30

A molecule is the smallest part of a covalent compound that can exist while retaining its chemical identity consisting of two or more atoms covalently bonded together

Question 31

One difference between ionic and covalent bonding ( direction of attraction)

Answer 31

A covalent bond is directional and acts solely between the atoms involved in the bond whereas in ionic it acts in all directions (the attraction in covalent is localised)

Question 32

What is a displayed formula

Answer 32

Shows the relative positioning of atoms and and the bonds between them as lines

Question 33

What is a lone pair of electrons

Answer 33

An outer shell pair of electrons that is not involved in chemical bonding

Question 34

What is a dative covalent bond

Answer 34

A shared pair of electrons which has been provided by one of the Covently bonded atoms only

Question 35

What are the rules for a dative covalent bond

Answer 35

Acceptor atom must be electron deficient so there is available orbitals for the electrons to occupy and dative bonds have the same length and strength as Normal covalent

Question 36

What is fulfilling the octet

Answer 36

Where compounds undergo covalent bonding and obtain the electron configuration of the nearest noble gas

Question 37

What are the exceptions to the octet rule

Answer 37

Not enough unpaired electrons to form an octet , more than 4 electrons are being used in bonding expansion

Question 38

What is expansion of the octet

Answer 38

From groups 5-7 from period 3 onwards more outer shell electrons are available and so can have more than 8 in outer shell

Question 39

What is bond energy

Answer 39

The energy needed to break the bond between two atoms and is measured in KJ/mol

Question 40

The amount of energy released when a bond is made is the same as

Answer 40

The energy taken in when a bond is broken

Question 41

What is the definition of a shell

Answer 41

A group of atomic orbitals with the same principal quantum number n also known as a main energy level