1.2 atomic orbitals, electronic configurations and the periodic table

Question 1

how can the discrete lines observed in atomic spectra be explained

Answer 1

if electrons, like photons, also display the properties of both particles and waves

Question 2

what do electrons behave as in atoms

Answer 2

stationary waves

Question 3

what are stationary/standing waves

Answer 3

waves that vibrate in time but do not move in space

Question 4

what are orbitals

Answer 4

the different sizes and shapes of standing waves possible around a nucleus

Question 5

how many electrons can an orbital hold maximum

Answer 5

2

Question 6

what is quanta

Answer 6

a fixed amount of energy that the electrons within atoms have

Question 7

what are the four quantum numbers

Answer 7

• the principle quantum number
• the angular momentum quantum number
• the magnetic quantum number
• the spin magnetic quantum number

Question 8

what is the principle quantum number shortened

Answer 8

n

Question 9

what is the angular momentum quantum number shortened

Answer 9

l

Question 10

what is the magnetic quantum number shortened

Answer 10

ml

Question 11

what is the spin quantum number shortened

Answer 11

ms

Question 12

what is the principle quantum number

Answer 12

this indicates the main energy level for an electron and is related to the size of the orbital

Question 13

what is the angular momentum quantum number

Answer 13

this determines the shape of the subshell and can have values from zero to n-1

Question 14

what is the magnetic quantum number

Answer 14

this determines the orientation of the orbital and can have values between -l and +l

Question 15

what is the spin magnetic number

Answer 15

this determines the direction of spin and can have values of +1/2 or -1/2

Question 16

what three rules are electrons within atoms arranged according to

Answer 16

• the aufbau principle
• hund’s rule
• the pauli exclusion theory

Question 17

what does the aufbau principle state

Answer 17

electrons fill orbitals in order of increasing energy

Question 18

what does hund’s rule state

Answer 18

when degenerate orbitals are available, electrons fill each singly, keeping their spins parallel before spin pairing starts

Question 19

what does the pauli exclusion principle state

Answer 19

no two electrons in one atom can have the same set of four quantum numbers, therefore no orbital can hold more than two electrons and these two electrons must have opposite spins

Question 20

what are the orbitals within each subshell of an isolated itom described as

Answer 20

degenerate

Question 21

what is the relationship between electronic configuration and ionisation energy

Answer 21

the more stable the electronic configuration, the higher the ionisation energy

Question 22

what is VSEPR

Answer 22

valence shell electron pair repulsion

Question 23

how do you calculate the number of electron shells

Answer 23

valence of central atom + number of atoms attached - charge of ion divided by 2

Question 24

how are electron pairs arranged

Answer 24

to minimise repulsion and maximise separation

Question 25

how many electron pairs for a linear shape

Answer 25

2

Question 26

how many electron pairs for a trigonal planar

Answer 26

3

Question 27

how many electron pairs for a tetrahedral shape

Answer 27

4

Question 28

how many electron pairs for trigonal bipyramidal

Answer 28

5

Question 29

how many electron pairs for octahedral

Answer 29

6

Question 30

what shape is a molecule with 2 electron pairs

Answer 30

linear

Question 31

what shape is a molecule with 3 electron pairs

Answer 31

trigonal planar

Question 32

what shape is a molecule with 4 electron pairs

Answer 32

tetrahedral

Question 33

what shape is a molecule with 5 electron pairs

Answer 33

trigonal bipyramidal

Question 34

what shape is a molecule with 6 electron pairs

Answer 34

octahedral

Question 35

how are the shapes of molecules or polyatomic ions determined

Answer 35

the shapes adopted by the atoms present based on the arrangement of electron pairs