Electron structure

Question 1

define electron shell

Answer 1

the orbit that an orbital is in around the nucleus of an atom

Question 2

define electron configuration

Answer 2

the arrangement of electrons

Question 3

define atomic orbital

Answer 3

a region around the nucleus that can hold up to two electrons with opposite spins

Question 4

what are the different types of orbitals

Answer 4

s-, p- , d- , f-

Question 5

what’s the valent shell

Answer 5

the outermost one

Question 6

the further the electron is from the nucleus, the ……………. the energy level

Answer 6

higher

Question 7

what’s principle quantum number

Answer 7

the number, n, used to number the energy levels

Question 8

how many electrons can the first shell hold

Answer 8

2

Question 9

how many electrons can the second shell hold

Answer 9

8

Question 10

how many electrons can the third shell hold

Answer 10

18

Question 11

how many electrons can the fourth shell hold

Answer 11

32

Question 12

how do you work out maximum number of electrons in shell

Answer 12

2n^2
n = principle quantum number (shell number)

Question 13

define first ionisation energy

Answer 13

energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form gaseous 1+ ions
A (g) —> A+(g) + e-

Question 14

IE1 is ……… when an e- is removed from a higher energy level

Answer 14

• lower
• decreasing IE1 consistent with increasing energy levels

Question 15

define successive ionisation energy

Answer 15

energy required to remove each electron one by one from 1 mole of gaseous atoms/ions

Question 16

what factors affect ionisation energy

Answer 16

• the greater the attraction between the e- and the nucleus the higher the IE
• atomic/ionic radius
• nuclear charge
• shielding - outer and inner e- repel, less attraction

Question 17

why is the IE2 of calcium and strontium greater than IE1

Answer 17

• the elements become more ionised (less e- so less repulsion)
• smaller ionic radius so greater electrostatic forces of attraction
• increased nuclear charge

Question 18

what’s the evidence for change of sub shell

Answer 18

small jumps in IE

Question 19

shape of s orbital

Answer 19

spherical

Question 20

shape of p orbital

Answer 20

dumb-bell

Question 21

how many orbitals are in the s subshell and how many e- can it hold

Answer 21

• 1, s orbital
• holds 2 e-

Question 22

how many orbitals are in the p subshell and how many e- can it hold

Answer 22

• 3, p orbitals
• holds 6 e-

Question 23

how many orbitals are in the d subshell and how many e- can it hold

Answer 23

• 5, d orbitals
• holds 10 e-

Question 24

how many orbitals are in the f subshell and how many e- can it hold

Answer 24

• 7, f orbitals
• holds 14 e-

Question 25

what does each subshell consist of

Answer 25

orbitals of the same type

Question 26

4d…

Answer 26

fills first and empties first

Question 27

what’s the evidence for change of shell

Answer 27

large jumps in IE

Question 28

there’s extra stability from ….. or ….. subshell

Answer 28

filled or half filled

Question 29

Hund’s rule

Answer 29

e- are added to orbitals singly with parallel spins before orbitals are occupied in pairs

Question 30

the most stable electronic configuration of an atom has the …. amount of energy

Answer 30

lowest

Question 31

what are the elements whose e- configuration are exceptions

Answer 31

• Cu
• Cr

Question 32

why does Cu have its unexpected e- configuration (involves 4s and 3d)

Answer 32

• Cu : 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^10
• half filled 4s and fully filled 3d provide more stability

Question 33

why does Cr have its unexpected e- configuration (involves 4s and 3d)

Answer 33

• Cr: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^5
• half filled 4s and 5d provide more stability