2.2.1 Shells and orbitals

Question 1

what is a shell?

Answer 1

a group of atomic orbitals with the same principal quantum number, n.

Question 2

what does n represent?

Answer 2

the principal quantum number (number representing the relative overall energy of each orbital)

Question 3

what does the principle quantum number indicate?

Answer 3

it indicates the shell that electrons occupy

Question 4

what does an increased value of n represent?

Answer 4

the larger the value of n, the further away the shell is from the nucleus (tf the higher the energy level)

Question 5

what is each shell made up of?

Answer 5

a number of atomic orbitals

Question 6

what is an atomic orbital?

Answer 6

a region around the nucleus that can hold up to 2 electrons, with opposite spin

Question 7

what are the four types of orbital?

Answer 7

SPDF

Question 8

what shape is an S orbital?

Answer 8

spherical

Question 9

from which shell upwards, contains S orbitals?

Answer 9

n=1 (first shell)

Question 10

how many S orbitals does each shell contain?

Answer 10

1

Question 11

how many S electrons does each shell contain?

Answer 11

2

Question 12

what shape does an P orbital have?

Answer 12

3D dumbbell shape

Question 13

from which shell upwards, contains P orbitals?

Answer 13

n=2

Question 14

how many P orbitals does each shell contain?

Answer 14

3

Question 15

how many P electrons could each shell contain?

Answer 15

6

Question 16

describe what planes each P orbital lies on?

Answer 16

px lying side to side
py top to bottom
p*z front to back

Question 17

from which shell upwards, contains D orbitals?

Answer 17

n=3

Question 18

how many D orbitals does each shell contain?

Answer 18

5 D orbitals

Question 19

how many D electrons could a shell contain?

Answer 19

10 D electrons

Question 20

from which shell upwards, contains F orbitals?

Answer 20

n=4

Question 21

how many F orbitals does a shell have?

Answer 21

7

Question 22

how many F electrons could a shell have?

Answer 22

14

Question 23

why do electrons not repel each other?

Answer 23

because an electron has a property of opposite spin

Question 24

describe ‘electrons in boxes’

Answer 24

represents orbitals as a box (with max 2 electrons)

Question 24

explain how electrons behave

Answer 24

like a particle and a wave

Question 25

what is electron configuration?

Answer 25

the arrangement of electrons in an atom

Question 26

which elements also have an F shell?

Answer 26

elements with more than 57 electrons (not in A Level course)

Question 27

what order does the energy of the electrons in sub shells increase?

Answer 27

s < p < d

Question 28

how many electrons can an atomic orbital hold?

Answer 28

2

Question 29

where do atomic orbitals exist?

Answer 29

at specific energy levels (electrons can only be found in these specific levels, not in-between them)

Question 30

how does the size of s orbitals increase?

Answer 30

the size of the s orbitals increases with increasing shell number

Question 31

how does the size of p orbitals increase?

Answer 31

the lobes of the p orbitals become larger and longer with increasing shell number

Question 32

what is spin pair repulsion?

Answer 32

when electrons with the same spin (clockwise or anti-clockwise) repel each other

Question 33

what is Hund’s rule?

Answer 33

electrons will occupy separate orbitals in the same subshell first to minimise this repulsion and have their spin in the same direction
They will then pair up, with a second electron being added to the first orbital, with its spin in the opposite direction

Question 34

what is the Pauli Exclusion Principle?

Answer 34

an orbital can only hold two electrons and they must have opposite spin

Question 35

why can two negatively charge electrons occupy the same orbital, even through there is repulsion?

Answer 35

the energy required to jump to a higher empty orbital is greater than the inter-electron repulsion

Question 36

what is ground state?

Answer 36

the most stable electronic configuration possible for an atom which has the lowest amount of energy